(Washington) Secretary of State Antony Blinken pledged U.S. support for the Armenia-Azerbaijan peace process in separate conversations with their leaders and called for opening the vital road for disputed enclave of Nagorny Karabakh.

These two Caucasian countries have clashed in two wars for control of Nagorny Karabakh, a mountainous region mostly populated by Armenians that seceded from Azerbaijan three decades ago.

During his talks with Azerbaijani President Ilham Aliyev on Sunday, Mr. Blinken “expressed the deep concern of the United States over the establishment by Azerbaijan of a roadblock at the entrance to the Lachin corridor that could undermine the efforts to build confidence in the peace process,” State Department spokesman Matthew Miller said in a statement.

Azerbaijan established a checkpoint last weekend at the entrance to this only road linking Armenia to the separatist region of Nagorny Karabakh.

Armenia considered this a violation of the ceasefire negotiated with Azerbaijan.

Mr. Blinken “stressed the importance of reopening the Lachin Road to commercial and private vehicles as soon as possible,” the statement added.

He told Mr. Aliyev of US support for the Azerbaijani-Armenian peace process, Mr. Miller said, and “shared his belief that peace is possible.”

The previous day, Mr. Blinken had also spoken with Armenian Prime Minister Nikol Pashinyan, Mr. Miller said in another statement released on Saturday.

The secretary of state also spoke of “the importance of the peace talks between Armenia and Azerbaijan” and “pledged the continued support of the United States,” according to Miller.

“The Secretary of State reaffirmed that direct dialogue and diplomacy are the only means to achieve a lasting solution,” the statement said.

With Russia increasingly isolated on the international scene since the start of its offensive in Ukraine, the United States and the European Union now play a major role as mediators in the process of normalization between Baku and Yerevan.