Armenia's prime minister has called his country's security relationships "ineffective," in a swipe at Russia after Azerbaijan claimed the breakaway province of Nagorno-Karabakh following a swift military campaign.

Armenia is part of the Collective Security Treaty Organisation (CSTO), a Russian-dominated group of six post-Soviet states, that, similar to NATO, requires members to come to each other's aid when under attack.

But this week, Azerbaijan forced the surrender of ethnic Armenian fighters in Nagorno-Karabakh, seemingly bringing to an end a conflict that has simmered for decades and raising the question whether Armenia could rely on long-term ally Russia.

"Armenia has never refused from its allied obligations and has never betrayed its allies," Armenia's Prime Minister Nikol Pashinyan said according to Armenia's public radio, going on to say that recent events had exposed the country's "vulnerabilities."

Pashinyan has previously criticized Russia for failing to inform him of Azerbaijan's plans, while some Russian commentators have mocked the prime minister for being unable to protect ethnic Armenians beyond its borders.

Although internationally recognized as part of Azerbaijan, Nagorno-Karabakh is home to 120,000 ethnic Armenians, who make up the majority of the population, and have created their own de facto government, rejecting Azerbaijani rule.

Presently, the Armenian government is working with partners to develop international mechanisms that will protect the rights of people in Nagorno-Karabakh. But if these efforts fail, Armenia will accept their "brothers and sisters... with all care," Pashinyan said.

"But this will not only fail to address the existing issues, but will further aggravate those," he warned.

Pashinyan's comments come as the first group of civilians arrived in Armenia from Nagorno-Karabakh.

A group of around 30-40 people, mainly women, children and elderly individual, are being registered at a humanitarian office, according to Armenia's Public Radio.

One local official in the disputed region, said that the bulk of Nagorno-Karabakh's Armenian population would leave for Armenia.

"Our people do not want to live as part of Azerbaijan. Ninety-nine point nine percent prefer to leave our historic lands," David Babayan, an adviser to Samvel Shahramanyan, the president of the self-styled Republic of Artsakh, told Reuters Sunday. The region is known as Artsakh to Armenians.

Azerbaijan says it will guarantee the rights of those living in the region. But Pashinyan and international experts have repeatedly warned of the risk of ethnic cleansing of Armenians in the enclave.

"The fate of our poor people will go down in history as a disgrace and a shame for the Armenian people and for the whole civilized world," Babayan said, adding that those responsible will have to answer before God for their sins.

"If the Armenians of Nagorno-Karabakh are not provided with real conditions to live in their homes and if no practical mechanisms of protection from ethnic cleansing are created, the probability that the Armenians of Nagorno-Karabakh will see the departure from their homeland as the only salvation will increase," Pashinyan said.

Both his and Babayan's comments come as the first aid since the ceasefire began, arrived in the landlocked region Saturday.

A convoy was transported along the Lachin corridor, the only road connecting Armenia to Nagorno-Karabakh, the International Committee of the Red Cross (ICRC) said in a statement on X, formerly known as Twitter.

The road has been blockaded since December 2022 by Azerbaijan, making it inaccessible to civilian and commercial traffic.

Azerbaijan's brief offensive ended in a Russia-brokered ceasefire in which separatist Armenian fighters agreed to surrender and lay down their arms.

At least 200 people were killed and over 400 others wounded in Azerbaijan's military operation, officials said.