Fifteen bodies have so far been recovered from the site of Monday's rocket strike on a refugee convoy of buses and cars in eastern Ukraine, a military spokesman said on Tuesday.
"By 7 p.m. last night we retrieved 15 bodies ... The search continued into the night and is continuing today," the spokesman, Andriy Lysenko, told Reuters.
The attack occurred near the city of Luhansk, close to the border with Russia, in an area where there had been intense artillery exchanges between government forces and pro-Russian separatists.
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The Kiev military blamed the attack on the rebels, but they have denied responsibility. At least one rebel leader suggested no attack had occurred.
The military said on Monday that many of those killed, who included women and children, had been burned beyond recognition. Many bodies had been blown apart by the blast.
The U.S. State Department condemned the attack on the convoy, which was near an area of heavy fighting between Khryashchuvatye and Novosvitlivka, but said it could not confirm who was responsible.
"We strongly condemn the shelling and rocketing of a convoy that was bearing internally displaced persons in Luhansk... Sadly, they were trying to get away from the fighting and instead became victims of it," State Department spokeswoman Marie Harf told a news briefing in Washington.
Ukrainian government forces have been fighting separatists for four months in the Russian-speaking east of Ukraine. The rebels have set up 'people's republics' and said they want to join Russia.
Ukraine says Russia, which seized the Crimean peninsula in March after a pro-Western government took power in Kiev, has orchestrated the uprisings and is arming the rebels with tanks, missiles and other heavy weaponry. Moscow denies this.