The Palestinian Authority has banned Al-Jazeera television from operating in its territory and threatened legal action over allegations it broadcast against President Mahmoud Abbas.
The Information Ministry said the Qatar-based Arabic news channel had spread falsehoods and incited viewers against the authorities that run the Israeli-occupied West Bank.
The ministry said allegations carried on Al-Jazeera on Tuesday and attributed to a senior figure in Mr Abbas's Fatah party, Farouq al-Qadoumi, were untrue.
The channel quoted Mr Qadoumi as saying Mr Abbas conspired with Israel to kill his predecessor Yasser Arafat in 2003. Mr Arafat died in a Paris hospital in 2004 of an undisclosed ailment.
"Al-Jazeera television has been devoting significant segments of its broadcasts to incitement against the Palestine Liberation Organisation and the Palestinian National Authority," the ministry said in a statement.
"Despite our repeated calls (on Al-Jazeera) to remain objective when it covers Palestinian affairs and to voice a balanced position regarding the internal Palestinian situation, the channel is still inciting," it said.
In a report on the ban, an Al-Jazeera presenter said the channel "expressed its astonishment about this decision by the Palestinian Authority and said it will issue a statement to answer the accusations of the Palestinian Ministry of Information".
Al-Jazeera, the presenter said, was one of several news operations to report remarks by Mr Qadoumi about an alleged scheme to kill Arafat. The broadcaster aired a half-hour special on the allegations.
In response to the ban, al-Jazeera again interviewed Mr Qadoumi, who insisted the information was authentic and urged the prosecution of Mr Abbas and other Palestinian officials - a call that could stoke more internal Fatah disputes.
"I don't doubt that some would try to bypass this genuine information rather than considering it and bringing to trial those who did it so we can tell right from wrong," he said.
Mr Qadoumi, who has no authority to try Mr Abbas, does not recognise Palestinian-Israeli interim peace deals nor the Palestinian Authority which they begat.
Palestinian officials had dismissed as smears Mr Qadoumi's accusations. They said he aimed at wrecking unity efforts within Fatah, which has been plagued by factional divisions.
Mr Qadoumi lives outside the Palestinian territories and has long been a critic of Mr Abbas.
Three Palestinian plain-clothes security men visited Al-Jazeera's bureau in Ramallah on Wednesday to deliver a written order to cease work.
"The staff of Al-Jazeera are not allowed to work, not allowed to broadcast, and crews are not allowed to work in the field until the judiciary issues its verdict," said Adnan Damiri, spokesman for the Palestinian security service.
"We will be monitoring them."
The Jerusalem-based Foreign Press Association issued a statement expressing deep concern and urging the Palestinian Authority to reconsider in line with its stated commitment to freedom of the press.
Relations between the Palestinian Authority and Al Jazeera grew tense after Hamas Islamists routed Mr Abbas forces in the Gaza Strip two years ago. The channel's correspondents have said that Mr Abbas aides and security officials were inciting against them.
Palestinian officials accuse the station of siding with Hamas, allegations Al Jazeera has denied. On occasion, Al Jazeera correspondents have been banned from Mr Abbas's office or ejected from it.