Formally, the peace agreement was not signed for one particular reason: there is still a provision in the Armenian constitution that casts doubt on Azerbaijan’s territorial integrity, Azerbaijani president Ilham Aliyev said in his interview with Al Arabiya television.

“So, the negotiations lasted, as I said, for several years and ended in Washington with the great support of President Trump and his team. Actually, I think that this is the end of the conflict, the end of the war. Formally, the peace agreement was not signed for one particular reason: there is still a provision in the Armenian constitution that casts doubt on Azerbaijan’s territorial integrity," Aliyev said.

"So, they [i.e. Armenia] will make an amendment, as far as we understand. As soon as this amendment to the constitution is made and territorial claims to Azerbaijan are deducted from the constitution, the formal peace agreement will be signed," he added.

But Aliyev did not express willingness to give up Azerbaijani territorial claims—presented under the name "Western Azerbaijan"—to Armenia.