Armenia and Azerbaijan have made "tangible progress" during marathon peace negotiations brokered by the US, Secretary of State Antony Blinken said Thursday at the conclusion of the five-day talks.

"The two sides have discussed some very tough issues over the last few days, and they've made tangible progress on a durable peace agreement," Blinken told reporters. "I hope that they see, and I believe that they do, as I do, that, there is an agreement within sight, within reach and achieving that agreement would be, I think, not only historic, but would be profoundly in the interests of the people of Azerbaijan and Armenia, and would have very positive effects, even beyond their two countries."

Blinken acknowledged the ongoing difficulties in the final stages of any prospective agreement, saying "The last mile of any marathon is always the hardest," but vowed to ensure the US's assistance "to continue to help both of our friends cross the finish line."

In near-identical statements issued following the talks, Baku and Yerevan acknowledged the progress referenced by Blinken, but said more work lays ahead.

"The Ministers and their teams advanced mutual understanding on some articles of the draft bilateral Agreement on Peace and Establishment of Interstate Relations, meanwhile acknowledging that the positions on some key issues remain divergent," the statements said.

"Both Ministers expressed their appreciation to the US side for hosting negotiations between Armenia and Azerbaijan. The parties agreed to continue the discussions," they added.

Armenian Foreign Minister Ararat Mirzoyan and Jeyhun Bayramov, his Azerbaijani counterpart, have been taking part in peace talks in the US capital since Sunday with meetings taking place at the White House and State Department.

On Monday, Blinken met separately with Bayramov and Mirzoyan at the George P. Shultz National Affairs Foreign Affairs Training Center in Arlington, Virginia.

Relations between the two former Soviet republics have been tense since 1991, when the Armenian military occupied Karabakh, which is internationally recognized as part of Azerbaijan, and seven adjacent regions.

Most of the territory was liberated by Baku during a war in the fall of 2020 which ended after a Russian-brokered peace agreement and opened the door to normalization.

However, the establishment of a checkpoint on the border between Azerbaijan and Armenia in the South Caucasus region last month sparked tensions.

The Azerbaijani Foreign Ministry said the border checkpoint was created in response to security threats from Armenia, citing the transfer of weapons and ammunition to the Karabakh region. Yerevan denied the charges.

Washington said previously that it was "deeply concerned" by Azerbaijan establishing a checkpoint on the Lachin corridor.