DONETSK, Ukraine: A bus driving near an army checkpoint in eastern Ukraine was hit by a rebel shell, killing at least 10 civilians and wounding a further 13, local officials said.

The Donetsk regional administration, which answers to the central government in Kiev, said in a statement that the rebels shelled the checkpoint near the town of Volnovakha in the Donetsk region while the passenger bus was passing through it.

The press office for military operations in the east said the rockets appeared to have been fired from a Grad multiple rocket launcher.

The Russian news agency Tass cited rebel officials as denying they were responsible for the attack and saying the accusation was “disinformation.”

Civilian losses of life have occurred on a regular basis since fighting broke out in spring between government forces and Russian-backed militia in the east. The UN estimates more than 4,700 people have died as a result of the conflict.

Hostilities have intensified in recent days, jeopardizing hopes for a peace deal.

Separatists and Ukrainian forces have traded accusations of violating a truce that had been in place since early December.

The United States will provide a $1 billion loan guarantee to embattled Ukraine if the government remains on track with an IMF-backed reform program, the Treasury Department said.

The assistance would be part of the international effort to support Ukraine, whose economy has been ravaged by Russia’s annexation of Crimea last year and continued fighting against pro-Russia insurgents in the country’s industrial east.