WASHINGTON — US Secretary of State Antony Blinken on Monday urged Azerbaijan’s leader to reopen a key corridor linking Armenia with the flashpoint enclave of Nagorno-Karabakh, warning that a blockade could reignite conflict with Yerevan.

Blinken spoke by telephone with Azerbaijani President Ilham Aliyev “to urge an immediate reopening of the Lachin corridor to commercial traffic,” State Department spokesman Ned Price said.

“He underscored that the risk of a humanitarian crisis in the Lachin corridor undermined prospects for peace between Armenia and Azerbaijan,” Price said in a statement.

Blinken last week also spoke with Armenian Prime Minister Nikol Pashinyan and voiced “deep concern for the worsening humanitarian situation in Nagorno-Karabakh” due to the blockage of the corridor.

For more than one month, protesters who claim to be environmental activists opposed to illegal mining have occupied the Lachin corridor, a 32-kilometer (20-mile) mountain road linking Nagorno-Karabakh to Armenia.

Armenia sees the protest as an attempt by Azerbaijan to destabilize Nagorno-Karabakh, a majority-Armenian enclave that remains recognized internationally as part of Azerbaijan but broke away after the fall of the Soviet Union.

Azerbaijan went on an offensive in 2021 and retook swathes of territory, claiming the lives of 6,500 people.

Blinken has been active on mediating between the two former Soviet republics, increasing US influence on an issue long dominated by Russia.

Russian peacekeepers were deployed to the Lachin corridor after the 2021 conflict but Armenia has voiced dismay at what it sees as Moscow’s failure to prevent the blockade due to its focus on the war in Ukraine.

Armenia, with a large diaspora in the United States, enjoys support in Congress where a group of lawmakers last week urged Blinken to consider sanctions on Azerbaijanis responsible for the blockade.

Led by Representative Frank Pallone, a Democrat, the lawmakers warned in a letter of a “potential humanitarian catastrophe” without “immediate action” by the United States.