Mariupol standoff (January 2015–present)

An attack on Mariupol was launched on 24 January 2015 by pro-Russian forces associated with the Donetsk People's Republic against the strategic maritime city of Mariupol, defended by the Ukrainian government forces. Mariupol had come under attack multiple times in the past year in the course of the War in Donbass, including in May–June 2014, when the city was under the control of pro-Russian forces; and the September 2014 offensive.

On 24 January 2015, the Mariupol city council and regional police said the city was subjected to indiscriminate rocket fire from the long-range Grad systems, killing at least 29 and injuring 97. The Ukrainian officials blamed the barrage on the rebels and the Russian military. According to Ukrainian intelligence, the attack was ordered by full-time Russian military commanders. The rebels denied the attack, but their leader, Alexander Zakharchenko, announced an offensive against Mariupol later that day.

According to a spot report by the OSCE Special Monitoring Mission to Ukraine, the Grad and Uragan rockets originated from the areas controlled by the pro-Russian forces. United Nations political chief Jeffrey D. Feltman said the attacks "knowingly targeted civilians," violated international humanitarian law, and could amount to war crimes.

Background
Mariupol and Battle of Debaltseve were high stake arenas for pro-Russian forces and Ukrainian forces as both cities are vital transport hubs, described as a "gateway to a land-bridge" to Russian-annexed Crimea, and strategically crucial to the pro-Russian objective of opening up and linking areas under their control with a view to securing the entire Donetsk and Luhansk regions.

On 22 January, pro-Russian rebels tried to attack Ukrainian positions on North-East of the city but failed. The next day, Alexander Zaharchenko vowed to fight until he reached the border of the Donetsk Oblast. Separatists reportedly began a tank offensive, and also conducted attacks near the west of the city. The village of Talakovka was reportedly shelled hard by separatists, but Ukrainian forces were "holding on". The shelling was confirmed by Andriy Lysenko, but said the separatists were still incapable of shelling the city itself because Ukrainian forces had not led them get close enough. Dmitry Tymchuk, a military blogger, reported on Facebook that a convoy of DPR tanks and APCs were advancing towards the city.

January 24 events
On 24 January, a major escalation took place after a rocket attack killed many people. Mariupol city authorities said that a Grad rocket hit a residential area in the city, and killed 20 people. Video footage showed that cars, buildings, and apartment flats were in flames as a result of the attack. The attack appeared to come from a multiple rocket launcher. One resident told Agence France-Presse on the telephone that the rebels had managed to seize Mariupol Airport, although rebels made no comment about that alleged airport seizure. The airport is located some 20 kilometers behind the front line. The rebels denied any involvement in the attack.

The rocket attacks came a day after the rebels rejected a peace deal and announced they were going on a multi-prong offensive against the government in Kiev to vastly increase their territory. Despite rebel denials, Donetsk rebel leader Alexander Zakharchenko said that his forces had started an offensive on Mariupol, and rejected further talks with Kiev; Zakharchenko said that "Today an offensive was launched on Mariupol. This will be the best possible monument to all our dead." Zakharchenko also stated that it is a provocation as DPR militants do not have mentioned artillery systems and according to his sourced the shelling was conducted from Staryi Krym. The death count also rose to 27 people, with several more injured. Ukrainian Prime Minister Arseniy Yatsenyuk called for an urgent meeting at the UN Security Council.

A Ukrainian military checkpoint was also hit in the attack, killing 1 soldier. The city council urged citizens of Mariupol not to panic and said that "all units are on fully battle-ready. Security measures in the city have been strengthened." The General Secretary of NATO Jens Stoltenberg condemned the attack, urging Russia to stop supporting the rebels. President Petro Poroshenko considered the attack a "crime against humanity", and cancelled his trip to Saudi Arabia. He also vowed to deliver a "full victory" over the rebels.

According to OSCE observers "Grad" and "Uragan" rockets were used in this attack, originating from villages Oktyabr (19 km NE) and Zaichenko (15 km NE), both controlled by separatist forces. Later, pro-Russian rebels said they were not going to storm Mariupol and the offensive was only to strengthen positions around the city.

The next day, President Poroshenko vowed to calm the recent fighting in the strategic port city. Speaking at an emergency meeting at the Ukrainian Security council, he said that the Minsk Protocol signed on September 5th was the only solution to end the conflict. He said intercepted radio conservations prove that pro-Russian rebels were behind the attacks, but the conservation hadn't been confirmed independently yet. Russia denied involvement in the attack, saying it was a result of Ukrainian forces shelling residential areas indiscriminately. Petro Poroshenko said Ukrainian forces killed most of rebels involved in the shelling, and put the rebel casualties at 110. Six Grad missile launchers were also destroyed according to him, and that the SBU captured the artillery gun spotter back to Kiev for questioning.

Security Service of Ukraine (SBU) published a detailed timeline of the rocket attack.

After the attack
On 27 January, Azov Battalion members started training outside Mariupol should a rebel attack occur. Two of its members were killed in an attack on a checkpoint near the city the next day. On 1 February, the villages of Talakovka and Pavlopol near Mariupol city were shelled heavily by pro-Russian rebels, according to Ukrainian forces. On 3 February, Separatists reportedly tried to attack Mariupol, but according to Ukrainian forces they claimed they destroyed two enemy tanks and a group of insurgents near the city.

On 4 February, Ukrainian SBU reported that they successfully completed a special operation to liquidate the detachment of Russian Army which conducted this attack.

Ukrainian counter-offensive
On 10 February, the National Guard and the Azov Battalion launched an offensive on the town of Novoazovsk. The offensive started when National Guard units broke through enemy lines. According to the Kyiv Post, the offensive was launched to stop rebels from shelling Mariupol and regaining its positions set by the Minsk Agreement. The Azov Battalion, however, stated that the offensive was launched to retake the town of Novoazovsk. The offensive was also launched to relieve pressure on the besieged town of Debaltseve. The Azov Battalion managed to capture the towns of Shyrokyne, Pavlopil, and Kominternovo, and were advancing towards Novoazovsk. Ukrainian flags, according to the battalion, were raised in Shyrokyne, Pavlopil, and Oktyabyr. Ukrainian forces managed to push the separatists back to Sakhanka, where the rebels were fighting back.

Fighting in Shyrokyne and renewed tensions
Heavy battles took place in the village of Sakhanka on February 11. On 14 February, an intense artillery battle took place in Shyrokyne. Many members of the Azov Battalion were wounded in the fighting, and some said that the village had virtually been destroyed. Ukrainian government forces managed to capture some prisoners, and the Azov Battalion said they expected more reinforcements to come.

On 25 February, the separatists recaptured Pavlopil and Pyshchevyk. On the same day, the Donbass battalion said that it destroyed a rebel fuel truck and an anti-aircraft gun in heavy fighting in Shyrokyne, which could be heard in the nearby village of Berdyanske where Ukrainian forces were building a second line of defense.

On 27 February, amid fears the rebels could be regrouping and preparing to attack Mariupol, a military spokesman said pro-Russian military equipment had been tracked leaving Donetsk in the direction of Mariupol.

On March 9, more fighting was reported near Mariupol. Ukrainian government forces accused the rebels of firing mortars and tank fire on the eastern edge of the city and attempting to drive Ukrainian forces out of Shyrokyne, a town which Ukrainian government forces control.

On April 5th, a landmine exploded under a military vehicle at Shyrokyne, a village east of the port of Mariupol, killing two soldiers and injuring a third, a military spokesman said on the TV channel 112.

International reactions
The attack was condemned in a public statement by the High Representative of the European Union for Foreign Affairs and Security Policy, Federica Mogherini. The condemnation by the United Nations Security Council was vetoed by Russia on the ground that the condemnation sought to blame Alexander Zakharchenko's announcement of beginning of the attack on Mariupol as being irresponsible and to condemn separatist forces who, according to Russia, are "self-defense forces". The attack and "provocative statements by self-defense leaders" were eventually condemned by UN Secretary-General Ban Ki-moon. The attack was also condemned by NATO.