Shelling from pro-Russia separatist rebels killed two Ukrainian soldiers in the country’s eastern Donetsk province this weekend, a Ukraine military spokesman said. Separately, the rebels accused Ukraine government forces of killing a civilian as hostilities continued in the ongoing conflict, despite last February’s ceasefire agreement.

Rebel artillery barrages were particularly intense near the contested port of Mariupol, which separatists have attempted to seize from Ukraine’s government for months, Agence France-Presse reports. An additional six Ukrainian soldiers were wounded in the attack, Ukraine military spokesman Andriy Lysenko said.

“Armed hostilities have risen significantly around [the Ukrainian city] Mariupol. The area of our positions being shelled has increased,” Lysenko said in a statement, according to Reuters.

Meanwhile, shells fired by Ukrainian government forces killed one civilian and injured two others in the city of Donetsk, the rebels claimed. The attack was “a grave violation of the Minsk agreement,” said rebel spokesman Denis Pushilin, in a reference to the ceasefire deal. Both sides have repeatedly accused each other of violating the deal’s terms since February.

Fighting continued in eastern Ukraine despite a planned summit in Paris Tuesday between foreign ministers from Ukraine, Russia, France and Germany, AFP noted. French and German officials were instrumental in brokering the initial ceasefire agreement, though the deal has been largely unsuccessful in preventing further violence. Russian officials have repeatedly denied allegations by western nations, including the United States and members of the European Union, that the Kremlin has provided direct support to separatist forces in eastern Ukraine.

“Paris must not turn into another blathering session," Ukrainian Foreign Minister Pavlo Klimkin told AFP. "Either we achieve concrete results, or we demonstrate clearly that Moscow does not want to fulfill the Minsk agreements."

More than 6,400 people have died and hundreds of thousands more have been displaced in the eastern Ukraine conflict since it began in early 2014. The United States and the European Union enacted sweeping economic sanctions against Russia late last year and were expected to keep the sanctions in place until Russia demonstrates a commitment to the peace process.