MOSCOW, April 29 (Reuters) - Armenia and Azerbaijan will hold a new round of talks in Washington on Sunday to try to normalise relations, the spokesperson of Armenia's Foreign Ministry said on Saturday.

Tensions have been rising again between the two countries over the disputed Nagorno-Karabakh region, where Russian peacekeepers were deployed in 2020 to end a war, the second that Armenia and Azerbaijan have fought over the enclave since the 1991 collapse of the Soviet Union.

The mountain region is internationally recognised as part of Azerbaijan but populated mainly by ethnic Armenians.

"From April 30 Minister of Foreign Affairs of Armenia Ararat Mirzoyan will be in Washington DC on a working visit. The next round of discussions on the agreement on normalisation of relations between Armenia and Azerbaijan is scheduled," the spokesperson, Ani Badalyan, said on her official Facebook page.

There was no immediate confirmation of the meeting by Azerbaijan.

Despite years of attempted mediation between them, Armenia and Azerbaijan have yet to reach a peace agreement that would settle outstanding issues such as the demarcation of borders and return of prisoners.

Azerbaijan set up a new checkpoint last Sunday on the road to Karabakh, the Lachin corridor, in a move that Armenia that called a gross violation of a 2020 ceasefire.