Internet services in the West Bank and Gaza have come under "sustained attack" by unknown hackers in multiple locations, according to officials.

"There has been a sustained attack since the morning from many sources in many countries," said Palestinian Authority spokesman Ghassan Khatib. "It is deliberate and continuous."

Computer experts were trying to identify the sources of the attack and the authority would seek assistance from the governments of those countries involved, he said. The attack had interrupted services, causing internet connections to range from "very, very slow to completely stopped".

The authority has no idea who was behind the cyber- attack and the reason for it, Khatib said.

The telecoms minister, Mashour Abu Daqqa, told Reuters that "all Palestinian IP addresses have been exposed to a focused, organised attack from abroad. I think this is organised by a state".

The attack came the day after the Palestinians won a symbolically significant victory at Unesco, which voted overwhelmingly on Monday to admit the Palestinian Authority as a full member. The move triggered punitive financial sanctions against the UN agency by the US.

Senior Israeli cabinet ministers were meeting on Tuesday night to consider their response to the Unesco vote. Hardline foreign minister Avigdor Lieberman said the government should consider cutting all ties with the authority and review its relations with Unesco.

After gaining the backing of 107 countries, with 14 voting against and 52 abstaining, the Palestinian leadership is considering membership applications to other global bodies to capitalise on its success.

The World Health Organisation and World Bank are among 16 agencies that could be presented with applications in the coming weeks. However, a Palestinian Authority official said it would await the outcome of a meeting of the United Nations security council next Friday that will consider a report on the Palestinians' request for full membership of the UN.

"If you ask are we studying options, the answer is yes we are, but no decision has been taken," said the official.

Ibrahim Khraishi, the Palestinian envoy at the UN in Geneva, said other international organisations and UN agencies were now a target.

"We are working on it, one by one," he told Associated Press. "Because it's now a precedent that we are a full member in one of the biggest and one of the most important UN agencies, Unesco. So it will open the door for us now to go further in our efforts to join other UN agencies."