A long and bloody battle has been raging near the eastern Ukrainian city of Slavyansk despite Kiev’s ceasefire. Self-defense fighters claim to have killed a whole platoon of Kiev’s National Guard, while the latter claim to have destroyed a militia tank.

READ MORE: Anti-Kiev forces in E. Ukraine pledge ceasefire till Monday

The Ukrainian forces shelled the outskirts of Slavyansk on Friday and hit the city with artillery fire, say reports from the scene, quoted by RIA Novosti. Following heavy shelling, Ukrainian troops took over a checkpoint seized by the self-defense overnight, witnesses said.

Several shells hit civilian houses in the nearby village of Golubovka, killing a 47-year-old woman and her 26-year-old son. The two reportedly had no time to take cover from the attack as their house was hit by the first shell that fell in the area.

Intense fighting on the outskirts of Slavyansk overnight into Friday was earlier confirmed by both sides.

#Славянск Сегодня при обстреле Голубовки погибли женщина и ее сын. И долго еще будет "перемирие"? pic.twitter.com/JJC0JywdJz — СЛАВЯНСК (@Sloviansk) June 27, 2014

The long and bloody battle centered on a checkpoint manned by the National Guard – troops loyal to Kiev that in March were formed from former and serving Ukrainian troops, Maidan self-defense squads, radical groups taking part in protests and from other volunteers, many of whom come from western Ukraine. The Slavyansk self-defense claims that the checkpoint was used as a strategic point in the relentless shelling of the city by the National Guard, which they say has continued despite the ceasefire.

Speaking to LifeNews on camera, the commander of the self-proclaimed Donetsk People’s Republic’s self-defense forces, Igor Strelkov, has claimed that “one [Ukrainian National Guard] platoon was definitely destroyed” in the fighting. Strelkov laid out a pile of documents that he said belonged to the deceased Ukrainian troops, showing that more than 20 troops had been killed in the fighting.

Some of the troops were killed by friendly artillery fire, Strelkov claimed, saying that the Ukrainian forces have orders to bombard the checkpoints seized by the self-defense. Nevertheless, self-defense managed to seize an APC, a mortar with ammunition, a “Fagot” (AT-4 Spigot) anti-tank missile system and three RPGs. Two more damaged Ukrainian APCs were also left near the checkpoint, as footage from the scene has shown.

Meanwhile, the National Guard issued a statement alleging that they lost only one soldier in the fight and that two more had been injured.

“As a result of a long-lasting skirmish that took place on the outskirts of Slavyansk, servicemen of the National Guard of Ukraine knocked out a tank. Among the servicemen of the National Guard of Ukraine there were losses: one soldier of the first reserve battalion was killed in battle, two were injured,” the statement read.

Strelkov has refuted the claim that a militia armored vehicle was damaged.

Talks, observers, or ‘tough action’?

The fighting took place hours after an OSCE mission visited the devastated city to inspect the humanitarian situation there. A member of the OSCE mission, Viktor Likhachyov, told LifeNews on Thursday that the observers will prepare a report to help create an “objective picture” of the situation in Slavyansk.

“The picture is grim; there is a lot of destruction. The experts have witnessed signs of mortar shelling, destroyed residential homes and infrastructure. I saw Slavyansk a month before – it was totally different,” Likhachyov said.

On Friday, Kiev and Donetsk People’s Republic (DPR) representatives met in the city of Donetsk for a second round of “consultations” on the peace plan for the region, ITAR-TASS reported.

The self-proclaimed people’s republics of Donetsk and Lugansk promised to observe a ceasefire until June 30, said the prime minister of the DPR Aleksandr Boroday following the meeting, RIA Novosti reported.

According to Boroday, anti-government activists will start negotiations with Kiev only after the Ukrainian military, the National Guard and Right Sector squads are withdrawn from the region.

The self-proclaimed republic is ready to invite OSCE observers to border territories and guarantee their safety, he added.

READ MORE: UN: 110,000 people fled Ukraine to Russia this year

Ukraine’s Interior Minister Arsen Avakov, meanwhile, said that the Ukrainian army is set for “tough actions” after the end of the truce in southeastern Ukraine.

“The country’s armed forces, the National Guard and subunits of the Interior Ministry are set for a solution to the problem,” the press service cited the minister as saying on Friday.

The statement came as Ukrainian President Petro Poroshenko told EU leaders in Brussels that he proposes extending the ceasefire for three more days to continue talks and exchange captives. The week-long ceasefire was scheduled to end at 10pm local time on Friday, following its extension by 12 hours earlier in the day.

Poroshenko’s peace plan has been welcomed by the West, but criticized by Moscow for resembling an “ultimatum” to the anti-Kiev east. There has been no mention of negotiations between Kiev and the self-proclaimed eastern Ukrainian authorities in the plan. Moreover, Poroshenko made threats of a “Plan B”, implying the use of force should his first proposal fail.

The EU meanwhile attempted to pressure Russia into accepting Poroshenko’s terms of the plan, with the European Council threatening Moscow on Friday with more sanctions if the situation in eastern Ukraine does not de-escalate within three days.