New fighting between Azerbaijan and Armenia has left some 150 soldiers and others dead. The violence has raised fears of instability spreading elsewhere in the former Soviet Union. It comes at a time when Russian forces are fighting in Ukraine.

Azerbaijan and Armenia contest the Nagorno-Karabakh region. Clashes there in 2020 killed over 5,600 people.
A Russia-mediated truce failed to end hostilities.

Armenia's prime minister has asked the Russian-led Collective Security Treaty Organization for military support. Armenia is a member of the alliance.

Meanwhile, border guards from Kyrgyzstan and Tajikistan exchanged fire on Wednesday, with both sides reportedly suffering casualties. The countries accuse each other of starting the fighting.

The leaders of all four former Soviet states had planned to take part in a summit of the Shanghai Cooperation Organization due to open Thursday in Uzbekistan.

But state-run media in Armenia say the country's prime minister will stay away.

Observers say Russian President Vladimir Putin will likely be worried about the friction among the former Soviet republics, which he sees as under Moscow's influence.