WASHINGTON (TASS) — U.S. National Security Adviser Jake Sullivan spoke separately over the phone on Monday with Acting Armenian Prime Minister Nikol Pashinyan and Azerbaijan President Ilham Aliyev, calling for talks on demarcating the border between the two countries, National Security Council Spokesperson Emily Horne said in a statement.

The statement says:

He [Sullivan] expressed concern over recent tensions between Armenia and Azerbaijan, and emphasized that military movements near un-demarcated borders are irresponsible and provocative. He welcomed the ongoing communication between the two sides and both leaders’ commitment to resolving this issue peacefully. In addition, he underscored the need for the two countries to conduct formal discussions to demarcate their international border.

Sullivan also “conveyed the commitment of the United States to peace, security, and prosperity in the South Caucasus”, as well as to “achieving regional reconciliation through bilateral engagement and as a Minsk Group Co-Chair” of the Organization for Security and Cooperation in Europe (OSCO).

According to the press service of Armenia’s head of government, at talks with Pashinyan the U.S. adviser stated that Washington would demand Azerbaijan withdraw troops from Armenia’s soil. Sullivan highly appreciated the restraint shown by Armenia in this situation and an attempt to iron out the issue by a diplomatic, not military means. The conversation was held at the initiative of the U.S. side.

On May 12, the Armenian Defence Ministry reported that the Azerbaijani forces attempted to carry out “certain activities” in one of the Syunik border region’s districts to “adjust the border”. The ministry added that the Azerbaijani troops halted their activities following some steps taken by Armenian forces.

In the evening of the same day, acting Armenian Prime Minister Nikol Pashinyan convened a meeting of the republic’s Security Council, during which he slammed these events as an encroachment on Armenia’s territory. According to Pashinyan, the Azerbaijani forces crossed Armenia’s border, moving 3.5 km into the country.