An airstrike in eastern Ukraine destroyed an apartment building Tuesday, killing at least 11 people and adding to the civilian death toll from the fighting between government forces­ and pro-Russian insurgents.

Rebels blamed the attack on the Ukrainian air force. The government denied blame but did not offer an alternative explanation.

The bombing in the rebel-held town of Snizhne demonstrated how airstrikes and heavy rocket fire are becoming increasingly common as the conflict drags into its fourth month. The attack comes one day after a Ukrainian military transport plane was shot down in disputed circumstances.

Health officials in the Donetsk region, which includes Snizhne, said 11 people died. Rescue workers pulled a small child with broken legs alive from the rubble as residents sifted for belongings.

Dmitry Tymchuk, a military analyst who coordinates closely with Ukraine’s Defense Ministry, said that there could be only one explanation for the bombing because rebels are unlikely to have any planes capable of carrying out such a strike. “Only Russian aviation could have performed the airstrike on Snizhne,” he wrote on his Facebook account.

The Ukrainian Defense Ministry stopped short of making that claim but insisted that the bombing could not have been carried out by its air force as none of its planes were on sorties at the time.

Andrey Lysenko, a spokesman for Ukraine’s National Security and Defense Council, called the incident a “cynical and bloody provocation” aimed at discrediting the armed forces.

No reliable updated death toll in the conflict is available, but hundreds of civilians are thought to have been killed. Authorities said Tuesday that 258 service members have been killed in fighting and 922 injured.

Representatives of the separatists’ self-proclaimed Luhansk People’s Republic said 12 civilians were killed Monday in the city in rocket attacks and airstrikes.

On Monday, Ukraine said a military cargo plane carrying eight people was shot down by a missile fired from Russian territory. Security Service chief Valentyn Nalyvaichenko said he had “unconditional evidence” of Russian involvement, the Interfax-Ukraine news agency reported Tuesday. Rebels said they shot the plane.