UN Secretary General Antonio Guterres is encouraged by news that long-time foes Armenia and Azerbaijan are ready to sign a peace treaty, his spokesman said Friday."The Secretary-General welcomes the announcements by Armenia and Azerbaijan on the conclusion of negotiations on the draft peace agreement,

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.

Armenian and Azerbaijani officials said on Thursday that they had agreed the text of a peace agreement to end nearly four decades of conflict between the South Caucasus countries, a sudden breakthrough in a fitful and often bitter peace process.