Moscow said that Russian officials discussed with Armenian equivalents the need to diffuse tensions with their archrival Azerbaijan over the Nagorno-Karabakh dispute late Tuesday.

Russian Deputy Foreign Minister Mikhail Galuzin met with Armenia’s two deputy foreign ministers and urged them to intensify efforts to normalize the situation in the region.

"The current situation in the region ... causes serious concern," the Russian Foreign Ministry said on its website. "The need to step up efforts on all tracks of the Armenian-Azerbaijani normalization as outlined by (cease-fire) agreements."

Azerbaijan on Sunday established a checkpoint at the start of the Lachin Corridor, the only road route linking Armenia to Karabakh, in what Armenia called a "gross violation" of a Moscow-brokered 2020 ceasefire agreement between the two sides.

The U.S. has said it was "deeply concerned" about the checkpoint.

Early Wednesday, the TASS news agency said Armenia appealed to the International Court of Justice (ICJ) over Azerbaijan’s checkpoint installation.

Karabakh is internationally recognized as part of Azerbaijan but was illegally occupied by Armenia for three decades.

In 2020, Azerbaijan made significant territorial gains in a six-week war that killed thousands on both sides before Moscow struck a cease-fire deal that included the dispatch of a Russian peacekeeping force to the region. The cease-fire is seen as a victory for Azerbaijan and a defeat for Armenia.

However, it has been violated several times since then, most notably in clashes in recent months that saw several service members from both sides killed.

Tensions between the former Soviet states over the Lachin corridor have soared since last year, with Russia focused on its offensive in Ukraine.

In December, Azerbaijani activists began protesting illegal mining on the Lachin road. Still, Yerevan accused Baku of blocking the route and creating a humanitarian crisis in the mountainous enclave, that Baku denied.

It said the checkpoint was "to prevent the illegal transportation of manpower, weapons, mines" by Armenia. However, it explained that it does not restrict the road’s use by Armenians in the region.

It also assured it would "be implemented with the Russian peacekeeping force."

In the meantime, the strain over the corridor has stalled negotiations on signing a peace treaty, including through international mediation.

Yerevan, which relies on Russia as a security guarantor, has grown frustrated over what it sees as Kremlin’s failure to fulfill its peacekeeping role.

The country is part of the Russia-led regional Collective Security Treaty Organisation (CSTO). It hosts a Russian military base, but increasing irritation with Moscow led to Yerevan scrapping plans to hold CSTO drills in January. However, it has so far refused to quit the pact altogether.

Many analysts say the small country cannot afford to abandon the CSTO, even as the U.S. and EU have taken the lead in peace talks.

In January, the EU launched a new civilian mission in Karabakh, which has drawn the Kremlin’s ire, with Russian Foreign Minister Sergei Lavrov accusing the West of "undisguised attempts ... to undermine the region’s security architecture."

Earlier this week, Moscow reiterated that it would continue to promote the implementation of the trilateral agreements between Russia, Azerbaijan and Armenia on Karabakh as "there is no alternative to them."