Palestinian security services in the Gaza Strip have been placed on a state of alert after a day of kidnappings.
Rashid Abu Shabak offered to quit over kidnappings in Gaza
Two of the most senior Palestinian security officials have offered to resign, but reports say Yasser Arafat has not accepted the resignations.
The Palestinian police chief in Gaza was briefly taken prisoner by gunmen, and four French aid workers were held.
Prime Minister Ahmed Qurei has called an emergency meeting to discuss the future of his government.
Amid speculation that the government might resign, Negotiations Minister Saeb Erekat told Voice of Palestine radio that everyone should shoulder their responsibility - "otherwise, we should give the chance to others to do so".
The declaration of the state of emergency reflects growing concern that the Palestinian Authority may be losing control over Gaza, says the BBC's David Chazan in Jerusalem.
Militant groups and factions appear to be struggling for power before a promised withdrawal of Israeli forces and Jewish settlers next year, our correspondent says.
Amin Hindi, the head of Palestinian general intelligence, and his colleague Rashid Abu Shabak, the preventive security chief in Gaza, said they were resigning "because of the state of chaos and the lack of action by the Palestinian Authority to make reforms".
Four French aid workers were seized on Friday evening by Palestinian militants in a cafe in the southern Gazan town of Khan Yunis.
Gunmen surrounded the building where the French were held
The four had been visiting Khan Yunis after it was twinned with the French town of Evry, in the Parisian suburbs.
Witnesses said gunmen took them to the local headquarters of the Palestinian Red Crescent, but they were all released after a few hours.
The leader of the kidnappers, Abu Qusai, told Reuters news agency that the hostages were freed after intervention by Mr Arafat, UN officials and the French diplomats.
A group called Abu Rish brigades said they had carried out the abductions to draw world attention to Palestinian suffering caused by Israel's occupation.
They also said they were protesting at public criticism of Yasser Arafat by the United Nations Middle East envoy Terje Roed-Larsen.
Police chief held
Earlier on Friday, the Palestinian police chief in the Gaza Strip, Ghazi Jabali, was freed after being abducted by gunmen.
He had been travelling in a motorcade on the coastal road south of Gaza City when gunmen opened fire and kidnapped him.
Mr Jabali was taken to the Bureij refugee camp in the central Gaza Strip, where he was reportedly held for several hours in a house surrounded by armed and masked militants.
He was freed after negotiations between Palestinian officials and the Jenin Martyrs' Brigades group holding him.
Jabali is unpopular in Gaza
The Jenin Martyrs' Brigades - a little known offshoot of the larger Popular Resistance Committees - did not say why it had carried out the abduction.
Another Palestinian official who serves as liaison officer with the Israeli army, Colonel Khaled Abu al-Ula, was reportedly released on Saturday after being kidnapped by subordinates overnight.
They were protesting against the possibility of losing their jobs, French news agency AFP reported.