BAKU/YEREVAN: Azerbaijan says 12 of its soldiers have been killed in fighting Saturday with Armenian forces over the separatist Nagorno-Karabakh region.

A Defense Ministry statement on Saturday also claimed that more than 100 Armenian forces had been killed or wounded. The ministry said one Azerbaijani helicopter was shot down and claimed to have destroyed six Armenian tanks and 15 artillery positions.

Heavy clashes erupted between troops from Azerbaijan and the rebel Nagorno-Karabakh region on Saturday, the two sides said, disputing who had violated a fragile cease-fire again. Nagorno-Karabakh’s military also said that Armenian anti-aircraft forces downed an Azeri helicopter, although the report was denied by Azerbaijan.

Nagorno-Karabakh, which lies inside Azerbaijan but is controlled by ethnic Armenians, has run its own affairs with heavy military and financial backing from Armenia since a separatist war ended in 1994.

Both sides report numerous casualties, accusing each other on Saturday of violating a cease-fire, a sign that the two-decade-old conflict which has left some 30,000 people dead is far from a peaceful resolution. Similar violence was reported last month.

“The enemy, using tanks, artillery and aviation made attempts to get deep into the defense lines of the Nagorno-Karabakh Army of Defense and capture tactical positions. The enemy was thwarted,” the Armenian Defense Ministry said in a statement.

War erupted over Nagorno-Karabakh in 1991 as the Soviet Union broke up, and killed about 30,000 people. A cease-fire was called in 1994 but violence has sporadically broken out since.