Azerbaijan on Wednesday accused Armenia of opening fire on its army positions along the Caucasus arch foes' shared border and in the disputed Nagorno-Karabakh region over which Baku and Yerevan have fought two wars.

The claims came a day after Armenian Prime Minister Nikol Pashinyan complained to President Vladimir Putin of "problems" with Russian peacekeepers in Nagorno-Karabakh and warned of an escalation in the volatile region.

"Azerbaijani army positions came under fire by Armenian forces at the border" overnight, the defence ministry in Baku said Wednesday.

No casualties were reported.

The ministry said there was also a shootout "from firearms of different calibre" in Karabakh, and that the Azerbaijani military "have taken adequate measures" in response.

Armenia's defence ministry dismissed the reports as "disinformation".

Both countries have been locked in a decades-long dispute for control of the Armenian-majority region of Nagorno-Karabakh. The latest conflict in 2020, which Azerbaijani won, ended with the deployment of Moscow's forces to keep the peace.

On Tuesday, Pashinyan said that he had recently spoken to Putin "of a possible escalation in Nagorno-Karabakh and said that there are problems in the zone where Russian peacekeepers are responsible."

At least three Armenians died in the latest border clashes earlier this month.

Pashinyan has also denounced Baku's ongoing blockade of the so-called Lachin corridor, Karabakh's sole land link with Armenia.

Yerevan has claimed that the blockade has led to a humanitarian crisis and was a "preparation for ethnic cleansing of Armenians." Baku has denied the accusations.

On February 20, the European Union deployed an expanded monitoring mission to Armenia's volatile border area as Western engagement grows in the region, the Kremlin's traditional sphere of influence.

When the Soviet Union collapsed in 1991, ethnic Armenian separatists in Karabakh broke away from Azerbaijan. The ensuing conflict claimed around 30,000 lives.

Another flare-up in violence in 2020 left more than 6,500 dead and ended with a Russian-brokered truce that saw Armenia cede swathes of territory it had controlled for decades.