Azerbaijani relaunched a full-scale attack on the Armenian controlled Nagorno-Karabakh on September 19 that the Defence Ministry said was the beginning of a “limited anti-terrorist operation”.

Russian peacekeepers are present around the enclave but pointedly took no action to prevent the re-start of the hostilities following a short war in 2020 that Armenia lost.

Baku said the operation aimed to “ensure the implementation of the trilateral agreement between Azerbaijan, Armenia and Russia of 2020” and “the disarmament and withdrawal of Armenian troops from the territory.”

Yerevan stringently denied it has any troops inside the Nagorno-Karabakh enclave that is overwhelmingly populated by Armenias, who are supposed to be protected by the Russian peacekeepers. Russia called on the sides to stop the bloodshed and try to work things out diplomatically.

Russia brokered the peace between fellow members of the Russian led- Collective Security Treaty Organisation (CSTO), the Former Soviet Union (FSU) version of Nato.

Russia is deeply alarmed by the sharp escalation of the situation in Nagorno-Karabakh, Russian Foreign Ministry Spokeswoman Maria Zakharova said. However, the Kremlin has been distracted by its own war in Ukraine and has been largely inactive in the growing crisis in the Caucuses. Azerbaijan has blockaded the enclave for months and refused to allow humanitarian aid into Nagorno-Karabakh where the situation has become increasingly desperate.

When the war started in 2020 Armenian President Nikol Pashinyan invoked Article 4 of the CSTO treaty that called for other members to come to its defence, but Moscow ignored the call.

Pashinyan has become so frustrated with Russia’s lack of action that he refused to host the CSTO military exercises this year, which have just finished in Belarus instead, and invited US troops to Armenia for the first time. Those exercises have just finished and the State Department announced on September 19 that the troops will leave on September 20.

Moscow called on the conflicting sides to stop the bloodshed and return to a political and diplomatic settlement. The Russian peacekeeping contingent in Nagorno-Karabakh reported numerous ceasefire violations from the Azerbaijani side, the Russian Defence Ministry reported at a press briefing but was taking no action.

"Since 12:00 p.m. of September 19, 2023, the Russian peacekeeping contingent has recorded numerous ceasefire violations from the Azerbaijani side along the entire line of engagement," Russian foreign minister spokeswoman Maria Zakharova said in a briefing.

According to Zakharova, Russia also is currently in talks on the situation in Nagorno-Karabakh, including with Azerbaijan. The ministry will make a statement on the results of these talks, she said.

Azerbaijan’s Defence Ministry said it plans to suppress "large-scale acts of provocation in the Karabakh economic region” that includes the disarmament and withdrawal of Armenian troops from the area. However, despite sporadic clashes on the line of contact, there have been no reports of Armenia aggression inside the Nagorno-Karabakh enclave in recent months.

That has changed now with reports of fighting right the way along the entire line of contact and the Defence ministry said Azerbaijani troops took control of more than 60 “combat positions” of Armenian units in Nagorno-Karabakh, according to Azerbaijani Defence Ministry Spokesman Anar Eivazov.

Russian peacekeepers in Nagorno-Karabakh have been largely inactive despite the fighting. The peacekeepers “keep doing their job,” but the situation in the region remains “difficult,” Russian Presidential Spokesman Dmitry Peskov told the media.

"The peacekeepers are fulfilling their functions, but the situation remains uneasy," Peskov said. "We see that, unfortunately, the current surge in tensions and the resumption of hostilities are a serious challenge and a serious threat first and foremost to civilians.”

Yerevan said that Baku seeks to "complete the policy of ethnic cleansing" and claims that Baku seeks to eject all the Armenians in the enclave or subdue them.

Azerbaijan denied reports circulating in the Armenian segment of global social networks about the shelling of civilian facilities in Karabakh by Azerbaijani units. Baku added that "only legitimate military targets are being put out of commission."

The Kremlin said the security of its peacekeepers was a top priority.

"Our forces stay in direct contact with the sides. All communication happens mostly via the military. So far, we have received no information that anything that could threaten lives of our peacekeepers has happened. Of course, this [security] is an important priority for us," Peskov said.

Peacekeepers have no right to use weapons as long as their lives are not under threat, the head of the State Duma’s Defence Committee, Andrey Kartapolov, told the Russian media.

Despite the escalating situation, Russian peacekeepers continue to carry out their mission. Russia assumes that the security of the peacekeeping contingent "will be unconditionally ensured by all sides."

Zakharova denied allegations that Azerbaijan had warned Russian peacekeepers ahead of today's "anti-terrorist operation." "This has no basis in reality. The information was communicated to the Russian contingent a few minutes before the start of hostilities," the spokeswoman said.

Armenia said it believes that "Azerbaijan has unleashed another large-scale act of aggression against the people of Nagorno-Karabakh, seeking to complete the policy of ethnic cleansing."

Prime Minister Pashinyan convened a meeting of the Security Council to discuss the situation. He said the situation on Armenia's borders is stable and Yerevan does not plan to take rash steps. Also, according to Pashinyan, Russian peacekeepers should respond to the situation in Nagorno-Karabakh.

The Turkish Foreign Ministry said that Azerbaijan has taken forced measures in Nagorno-Karabakh by launching an anti-terrorist operation.

"Today, on September 19, the Azerbaijani army launched an anti-terrorist operation aimed exclusively against military elements. There were no decisions in response to the legitimate and well-founded concerns that Azerbaijan has continuously expressed for almost three years since the end of the second Karabakh war. Azerbaijan was forced to take measures it deems necessary on its sovereign territory," the ministry said in a statement.