DUBAI - Lebanon expects a written offer from U.S. mediator Amos Hochstein concerning the demarcation of a maritime border with Israel by the end of the week, Lebanon's presidency tweeted on Monday.

Lebanon's deputy speaker of parliament Elias Bou Saab met with Hochstein last week during a visit to New York and briefed President Michel Aoun on the outcome, the presidency added.

Hochstein has been shuttling between Lebanon and Israel - enemy states with a history of conflict - in a bid to forge a compromise over the maritime boundary that would allow both to explore for offshore energy reserves.

A deal would defuse one potential source of conflict between Israel and the heavily armed, Iran-backed Lebanese group Hezbollah, which has warned against any Israeli exploration and extraction in the disputed waters.

(Reporting by Moataz Mohamed and Omar Fahmy; Writing by Lina Najem/Tom Perry; Editing by Frank Jack Daniel and Ed Osmond)