Azerbaijan is to launch major military exercises near the breakaway Nagorny Karabakh region, its defence ministry said Friday, two months after fierce clashes with ethnic-Armenian separatists over the disputed territory.

The "operational-tactical exercise will be held from 19 to 24 of June with all the arms and services," the Caucasus nation's defence ministry said in a statement.

The drills will take place in "military ranges located in the (Karabakh) frontal zone, and in the Nakhichevan Autonomous Republic, as well as the Azerbaijan sector of Caspian Sea set up," the ministry said.

They will involve "about 25,000 servicemen, more than 300 tanks and armoured combat vehicles, more than 100 rocket artillery launchers, up to 40 military aircraft and more than 30 air defence systems, ships of naval forces and special forces units."

Fighting erupted in Nagorny Karabakh in early April, killing at least 110 people and wounding scores more before a Russia-mediated truce ended the worst of the violence.

The crisis has long festered, with dozens killed every year, but April's fighting was the worst since a 1994 ceasefire turned it into one of Europe's frozen conflicts.

Azerbaijan and Armenia have feuded over Nagorny Karabakh since Armenian separatists seized the landlocked territory in a war that claimed some 30,000 lives in the early 1990s.

Energy-rich Azerbaijan, whose military spending exceeds Armenia's entire state budget, has repeatedly threatened to take back the breakaway region by force.

But Moscow-backed Armenia has vowed to crush any military offensive.