Armenia and Azerbaijan will not deploy third-country forces along their border after the two sides sign a peace agreement, Armenian Prime Minister Nikol Pashinyan said on Thursday.

But hurdles remain. Azerbaijan also said Armenia’s constitution must “eliminate the claims against the sovereignty and territorial integrity of Azerbaijan,” as a prerequisite to allow for the signing of the peace treaty.

Armenia and Azerbaijan on Thursday said they had agreed to sign a peace deal after decades of conflict, with Armenia agreeing to surrender its claim over the primarily Armenian-populated Karabakh region.