The leader of the Palestinian Islamist movement Hamas, Khaled Meshaal, has effectively abandoned his headquarters in the Syrian capital, Damascus, diplomatic and intelligence sources said on Friday.

"Meshaal is not staying in Syria as he used to do. He is almost out all the time," said a diplomat in the region who spoke on condition on anonymity.

A regional intelligence source, who also did not wish to be identified, said: "He's not going back to Syria. That's the decision he's made. There's still a Hamas presence there, but it's insignificant."

Damascus is isolated following a bloody, 10-month uprising against the rule of President Bashar al-Assad and is not secure, the diplomat said, adding that Meshaal was no longer able to receive international visitors there.

Analysts say Meshaal was also embarrassed by Assad's violent crackdown, with more than 5,000 people reported killed. Many victims of the security forces have been Sunni Muslims allied to the Muslim Brotherhood, whose support Meshaal relies on.

Assad is backed mainly by his minority Alawite sect and other minorities.

The sources said Meshaal would not publicly shut down the political headquarters of Hamas in Syria, where it has long been hosted by Assad and by his father before him.

"In the past month he may have only stayed five days in Syria and the rest he spent in Qatar, Turkey and Egypt," said the diplomat. "But he did not close the headquarters in Syria in full and there are some Hamas officials still there."

"Our belief is that Hamas will not announce a departure from Syria even if it happened," the diplomat added.

The sources said Meshaal was currently in Egypt. But "there was no agreement to open an office in Cairo. Not yet," said the diplomat. "The expected residence for Meshaal is Qatar where he may stay most of the time until the Syria smoke has cleared."

Qatar is the Arab world's most outspoken critic of Assad. Qatari mediation was helpful in arranging Meshaal's upcoming visit to Jordan next week, restoring ties with the monarchy more than a decade after Hamas was ejected from the kingdom.

Hamas, founded in 1987 and regarded by Israel and the West as a terrorist organisation, has long been backed by Iran, a strong ally of Syria's Assad. But funding has apparently stalled in the past four months, the diplomat said.

"Iran used to give $250 million to $300 million to Hamas but there have been interruptions in the payments in past year. Our understanding is that there has been no payment since August 2011," he said.

Hamas Gaza Strip leader Ismail Haniyeh was thought to have "received promises from Turkey to provide the movement and his administration with $300 million a year to help Gaza".

Turkey is also a strong critic of the crackdown by Assad in its southern neighbour, Syria. Haniyeh is scheduled to travel to Iran in the coming days.