(Reuters) - Fresh clashes erupted between Azerbaijan and Armenia on Wednesday as international efforts intensified to end violence that killed nearly 100 soldiers in the deadliest fighting between the ex-Soviet republics since 2020.

The Armenian defence ministry accused Azerbaijan, which is backed politically and militarily by Turkey, of firing artillery, mortar and small arms in a fresh attack.

"The situation on the Armenian-Azerbaijani border remained tense," the defence ministry said.

At least 49 Armenian and 50 Azerbaijani military were killed on Tuesday in clashes along the countries' border, prompting an appeal for calm from Russian President Vladimir Putin. Both sides blamed each other for the fighting . read more

The clashes have raised fears of another major armed conflict in the former Soviet Union while Russia's military is tied up with the invasion of Ukraine.

A full-fledged conflict between Armenia and Azerbaijan would risk dragging in Russia and Turkey, and destabilise an important corridor for pipelines carrying oil and gas just as confrontation over Ukraine disrupts energy supplies.

Azerbaijan accused Armenia, which is in a military alliance with Moscow and home to a Russian military base, of firing mortars and artillery against its military units. It said that two civilians had been injured since the clashes erupted.

"Our positions are periodically being fired against at the moment," Azerbaijan's defence ministry said. "Our units are taking the necessary response measures."

On Tuesday, Armenia said its neighbour struck well inside its territory, including Jermuk, a resort town known for its hot springs.

Reuters was unable to immediately verify battlefield accounts from either side.