KIEV (Reuters) - The number of Ukrainian soldiers killed in an offensive by pro-Russian separatists over the past two days has risen to seven, Ukraine’s military said on Monday, in the deadliest outbreak of fighting in the east of the country since mid-December.

The clashes between Ukraine’s military and the pro-Russian separatists coincide with U.S. President Donald Trump’s call for better relations with Moscow that has alarmed Kiev while the conflict in its eastern region remains unresolved.

The rebels began attacking government positions in the eastern frontline town of Avdiyivka on Sunday, Ukrainian officials said. Five soldiers were killed and nine wounded on Sunday and two more were killed on Monday, they said.

“The situation in the Avdiyivka industrial zone is challenging. The enemy continues to fire at our positions with heavy artillery and mortars,” Ukrainian military spokesman Oleksandr Motuzyanyk told a regular daily briefing.

The separatist website DAN said on Monday shelling by Ukrainian troops had killed one female civilian and wounded three others in the rebel-held town of Makiyivka, south of Avdiyivka. The reports could not be independently verified.

On Sunday the separatists said one of their fighters had been killed during heavy Ukrainian shelling of their positions.

Both sides accuse the other of violating a two-year-old ceasefire deal on a near-daily basis.

Close to 10,000 people have been killed since fighting between Ukrainian troops and rebels seeking independence from Kiev first erupted in April 2014.

Ukrainian President Petro Poroshenko was due to discuss the state of the conflict on Monday in Berlin with German Chancellor Angela Merkel, who helped broker the Minsk ceasefire deal.

Ukraine and NATO accuse the Kremlin of supporting the rebels with troops and weapons, which it denies. The United States and European Union have imposed sanctions on Russia over the conflict, as well as for its annexation of Ukraine’s Crimea peninsula.

Ukraine is anxious that international resolve to hold Russia to account may waver following the election of Trump, who has spoken of possibly lifting sanctions against Moscow.

Trump spoke with Russian President Vladimir Putin on Saturday and the two men agreed to try to rebuild strained ties and to cooperate in Syria.