The deal was signed by the two foreign ministers after last-minute problems delayed the ceremony in Switzerland.

Under the agreement, Turkey and Armenia are to resume diplomatic ties and re-open their shared border.

The accord has been met by protests in Armenia, where many people say it does not fully address the 1915 killing of hundreds of thousands of Armenians.

Armenia wants Turkey to recognise the killings as an act of genocide, but successive Turkish governments have refused to do so.

The agreement calls for a joint commission of independent historians to study the genocide issue.