A senior adviser to Palestinian President Mahmoud Abbas's government was abducted by gunmen in the Hamas-controlled Gaza Strip on Friday, Mr Abbas's Fatah faction has claimed.
Fatah said Omar al-Ghoul, who advises Prime Minister Salam Fayyad, was taken from his home in Gaza one day after he arrived in the coastal territory from the occupied West Bank.
Mr Ghoul has been living in the West Bank city of Ramallah, where Fayyad's government is based, for the last three months. It was not immediately clear why he returned to Gaza, where his family lives.
Mr Fayyad's information minister blamed "criminals working for Hamas" for the abduction and called for his immediate release.
Hamas denied any involvement and said its forces were investigating.
It was the highest-profile abduction since Hamas Islamists seized control of the Gaza Strip in June after routing secular Fatah forces.
Tensions between Hamas and Fatah remain high in Gaza, where an explosion took place during a funeral procession for three militants killed in an Israeli air strike yesterday. At least two mourners died and 35 were wounded.
Hamas security sources said a gunman appeared to have accidentally dropped a hand grenade into the crowd.