The United Nations has sharply criticized both the Ukrainian government and pro-Russian rebels for turning bus stops, schools, markets and hospitals into battlegrounds where civilians are getting killed.

Indiscriminate shelling and an escalation in the fighting in eastern Ukraine have killed at least 224 civilians in the past three weeks alone, the UN said, raising the overall death toll to 5,358 since April.

Hostilities between Russian-backed separatists and Ukrainian troops resumed with a vengeance in January after a month of relative calm. The latest peace talks broke down Saturday, with both sides blaming the other for prolonging the fighting.

"Bus stops and public transport, marketplaces, schools and kindergartens, hospitals and residential areas have become battlegrounds … in clear breach of international humanitarian law," UN High Commissioner for Human Rights Zeid Ra'ad Al Hussein said, adding that 545 civilians were wounded in the last three weeks as well.

He blamed the high civilian death toll on "the indiscriminate shelling of residential areas in both government-controlled territory and in areas controlled by the armed groups." The UN estimates more than 5 million people still live in the conflict zone.

More casualties

Rebels in the separatist stronghold of Donetsk said Tuesday that artillery fire killed at least eight people and wounded 22 others in the past day, while Ukrainian military spokesman Andriy Lysenko said five servicemen had been killed and 27 wounded in the same period.

Ukraine accuses Russia of arming the rebels, a charge that Russia denies. But Western military experts say the sheer amount of heavy weapons in rebel hands belies that denial. The U.S. and the European Union have imposed economic sanctions on Russia for its actions in Ukraine.

In another development, mother of seven accused of spying for Ukraine was released from custody in Russia on Tuesday following public outrage.

Svetlana Davydova, a mother of seven, who lives in the city of Vyazma in western Russia is released from jail in Moscow after being arrested last month on treason charges for providing Ukraine with information on Russian troops movements. She still faces a trial on the charges. (Pavel GolovkinAssociated Press) Even though Svetlana Davydova was freed, charges against her are still pending. Her youngest child is a 2-month-old baby whom she was breastfeeding.

Davydova, 37, was arrested Jan. 21 at her home in the town of Vyazma, west of Moscow. The Federal Security Service, the main KGB successor, had detained her on charges of treason that carry a prison sentence of up to 20 years.

Investigators haven't revealed details of the accusations, but media reports said Davydova called the Ukrainian Embassy after she had overheard a serviceman on a bus saying he and his comrades were preparing for a trip and decided he was talking about being sent to Ukraine.

Davydova has turned down a lawyer provided by the state and repudiated her initial testimony to investigators after hiring new lawyers.