President Donald Trump has overturned decades of US policy by saying it is time to recognise Israel's sovereignty over the occupied Golan Heights, which it captured from Syria in 1967.
In a tweet, Mr Trump declared that the plateau was of "critical strategic and security importance to the State of Israel and regional stability".
Israel annexed the Golan in 1981 in a move not recognised internationally. Syria, which has sought to regain the region, has so far made no comments.
Israeli Prime Minister Benjamin Netanyahu - who has warned about the "military entrenchment" of his country's arch-enemy Iran in Syria and has ordered air strikes in an attempt to thwart it - tweeted his thanks to Mr Trump.