A jailed Ukrainian pilot on Friday refused to give up a hunger strike, after rejecting food and water in protest at delays in her controversial murder trial in Russia, her lawyers said.

Nadiya Savchenko, 34, is demanding she be repatriated to Ukraine after a judge in the southern Russian town of Donetsk on Thursday unexpectedly postponed her final address to court as her trial over the 2014 killing of two Russian journalists in east Ukraine nears an end.

Ukrainian pilot Nadiya Savchenko, who is on trial over the killing of two Russian journalists in war-torn Ukraine, said Thursday she was going on hunger strike and would refuse both food and water.

Savchenko announced the move in court, saying it was in protest at a decision to adjourn the proceedings until next week, one of her lawyers told AFP.

Ukraine on Thursday accused pro-Russian insurgents of firing large-caliber weapons at its forces in advance of new peace talks in Paris aimed at ending the 23-month war.

The charge came one day after Kiev and rebel envoys agreed to halt live-fire exercises along the 500-kilometer (300-mile) front splitting eastern separatist territories from the rest of the West-leaning former Soviet state.

Despite a lull in fighting in east Ukraine, the low-level conflict between government forces and rebels continues to "significantly affect" civilians, the U.N. said Thursday as talks on the stalled peace process were to resume.

Talks on the Minsk agreement signed a year ago and aimed at forging a political solution to the nearly two-year war were to resume in Paris on Thursday, grouping foreign ministers from Russia, Ukraine, France and Germany.

Russia's state prosecutor on Wednesday demanded a 23-year prison sentence for Ukrainian pilot and lawmaker Nadiya Savchenko who is accused of killing two Russian journalists in war-torn Ukraine.

One of Savchenko's lawyers, Mark Feigin, told AFP the prosecution had also requested she pay a fine of 100,000 rubles ($1,350/1,250 euros).

A Ukrainian soldier has been killed in a new bout of clashes with pro-Russian insurgents in the separatist east of the country, a Kiev military official said Friday.

Ukrainian military spokesman Andriy Lysenko said the incident occurred close to the government-held village of Granitne, about 50 kilometers (30 miles) south of the rebels' de facto capital Donetsk.

Ukraine's Prime Minister Arseniy Yatsenyuk hit out Friday against President Petro Poroshenko and his camp, accusing them of undermining key reforms that are badly needed to overcome the ex-Soviet state's economic malaise.

In an interview with the Frankfurter Allgemeine Zeitung daily, Yatsenyuk also warned Poroshenko that if he were forced out from government, it could jeopardize the delivery of a massive IMF-led rescue package.

The mayor of a government-controlled town in war-torn eastern Ukraine has been shot dead, the police said Tuesday, adding that it was not immediately clear who carried out the attack.

Volodymyr Zhyvaga, 44, was mayor of Starobilsk, a town of about 20,000 located 80 kilometers (50 miles) northwest of the pro-Russian separatist-held city of Lugansk.

Ukraine's pro-EU ruling coalition pulled back from the brink on Thursday after one junior partner withdrew while a populist party announced plans to step in and pull the country "out of the abyss."

The war-scarred former Soviet republic has been riven by weeks of political chaos that culminated in a failed bid by parliament on Tuesday to oust Prime Minister Arseniy Yatsenyuk's government over its perceived failure to fight graft.

Russia has filed a lawsuit against Ukraine at the High Court in London over a disputed $3 billion loan that Moscow says Kiev has refused to pay back, the finance minister said Wednesday.

"Today the Russian finance ministry filed the lawsuit against Ukraine with the goal of recovering debt on Ukraine's bond with the nominal value of $3 billion," Finance Minister Anton Siluanov was quoted by Russian news agencies as saying.