Hamas officials say senior members of their exiled leadership will evacuate their families from the group's headquarters in Syria.
Hamas, a militant Islamist Palestinian group, rules the Gaza Strip.
The officials, speaking from Damascus, said Tuesday that the evacuations are in response to the deteriorating security situation in Syria, where President Bashar Assad has been resisting a 10-month uprising.
The officials say the families of three top officials, Moussa Abu Marzouk, Mohammed Naser and Izzat Risheq, are set to leave at the end of the month, while the three men will remain in Damascus.
In recent months, Hamas has pulled lower level officials and their families out of Syria.
The officials spoke on condition of anonymity because they were discussing the inner workings of the secretive group.
The announcement comes hours after Syria said it would not object to extending an Arab League mission to monitor its compliance with a peace plan, but will not accept an expansion in the scope of its mandate, an Arab source said on Tuesday.
An Arab League observer team in Syria since late December is expected to report this week that Damascus has failed to fully implement a peace deal plan aimed at ending 10 months of violence.
The mission's mandate expires on Thursday, and Arab League foreign ministers are set to discuss its future when they meet on Jan. 22.
"The outcome of the contacts that have taken place over the past week between the Arab League and Syria have affirmed that Syria will not reject the renewal of the Arab monitoring mission for another month... if the Arab foreign ministers call for this at the coming meeting," the source said.
Some Arab countries say the monitors need a broader mandate to help stop violence, if the mission is to be continued. Qatar has even suggested sending Arab troops.
The source said Syria would agree to allow the number of monitors - now fewer than 200 - to be increased, but would not allow them to be given formal fact-finding duties or to be allowed into "military zones" that are not yet agreed.