YEREVAN -- Armenia has formally appealed to the Russian-led Collective Security Treaty Organization (CSTO) to hold consultations on its border dispute with Azerbaijan that has emerged months after the two countries ended a war over the breakaway region of Nagorno-Karabakh.

Caretaker Prime Minister Nikol Pashinian invoked Article 2 of the CSTO founding treaty committing the bloc to "immediately launch the mechanism of joint consultations" on a collective response to threats facing a member state, his office said on May 14.

Besides Armenia and Russia, the grouping also includes Kazakhstan, Kyrgyzstan, Tajikistan, and Uzbekistan -- but not Azerbaijan.

Armenia has accused Azerbaijani troops of crossing several kilometers into its southern border and trying to stake claim to territory.

Azerbaijan rejects the claim, saying its troops were taking up positions on the Azerbaijani side of the border and in turn accused the Armenian leadership of trying to exploit the matter for political reasons ahead of snap parliamentary elections next month.

The fresh escalation of tensions comes after a six-week conflict between Armenia and Azerbaijan claimed some 6,000 lives. It ended in November with a Moscow-brokered cease-fire that saw Armenia ceding swaths of territory that ethnic Armenians had controlled for decades.

Pashinian informed Russian President Vladimir Putin of his decision to turn to the CSTO during a phone call late on May 13, his office said.

During the call, Putin stressed the need for "strict observance" of the cease-fire agreement, and "reaffirmed [Moscow's] commitment to active mediation efforts and close contacts with Yerevan and Baku, aimed at ensuring stability in the region," according to the Kremlin.

On May 14, Armenia's parliament gathered in an emergency meeting and adopted a statement on the "crisis situation in border districts" amid the incident with Azerbaijan.

Pashinian told parliament that the Azerbaijani moves amounted to a "large-scale provocation."

Meanwhile the U.S. State Department said on May 14 that Washington was closely monitoring the situation along the border between Armenia and Azerbaijan, after urging both sides the previous day to show "restraint in de-escalating the situation peacefully."

Earlier, French President Emmanuel Macron demanded that Azerbaijan immediately withdraw its troops from Armenian territory they had "invaded."

After speaking with Pashinian, Macron wrote on Facebook: "Azerbaijan's armed forces have invaded Armenian territory. They must be immediately withdrawn."

"To the Armenian people, I once again say: France stands in solidarity and will remain so," he added.

The French president also expressed hope that the UN Security Council could help to "restore stability and security in this region," his office said in a statement.

According to an Armenian readout of the call, Pashinian thanked Macron for his "friendly attitude" toward Armenia.

Yerevan accuses Azerbaijani forces of moving 3 1/2 kilometers into Syunik Province early on May 12, and of breaching two other sections of the Armenian-Azerbaijani border the next day.

Azerbaijan insists that its troops did not cross into Armenia and simply took up positions on the Azerbaijani side of the frontier which were not accessible in winter months. It added that the border between the two South Caucasus states wasn't demarcated after the breakup of the Soviet Union.

"We believe that attempts by official circles to use this issue for political purposes in connection with the preelection situation in Armenia are unacceptable," the Foreign Ministry said.

The conflicting statements came as Armenian and Azerbaijani military officials met on the border to try to resolve the dispute. Representatives of Russian troops deployed in Syunik also reportedly took part in the negotiations that lasted for several hours. No concrete agreements were announced afterward.

Under the Moscow-brokered cease-fire deal signed in November, a part of Nagorno-Karabakh and all seven districts around it were placed under Azerbaijani administration after almost 30 years of control by Armenians.

Nagorno-Karabakh is internationally recognized as part of Azerbaijan, but the ethnic Armenians who make up most of the region's population reject Azerbaijani rule.

With reporting by Reuters and TASS