Palestinian group Hamas has received an official invitation for talks in Russia, a leader of the faction said in the Gaza Strip on Thursday.

Khalil Abu Laila said the invitation was sent to Hamas politburo chief Khaled Meshaal, who lives in exile, and that a date for the visit would be agreed later.

Hamas had already said it would accept Moscow's invitation, which has upset Israel and the United States by challenging their campaign to isolate the group unless it renounces violence and recognizes the Jewish state's right to exist.

The Russian initiative has seemed to open a crack in the Quartet of Middle East mediators -- including the United Nations, European Union and Washington.

But Russian Foreign Minister Sergei Lavrov said on Wednesday that Moscow agreed that Hamas must commit to seeking peace with Israel to win international acceptance.

"We will work toward Hamas accepting the Quartet's positions. This is not just the Quartet's opinion but also that of the majority of nations, including Arab nations," he said after talks with EU leaders in Vienna.

PHOTO CAPTION

Senior Hamas legislator, Ahmed Haj Ali, 65, embraces his grandson at the Hawara checkpoint in the West Bank city of Nablus Wednesday Feb. 15, 2006. (AP)