Palestinian Authority President Mahmoud Abbas has accused Hamas of trying to establish its own state in Gaza.
Mr Abbas condemned Hamas as "murderous terrorists" and "coup plotters", over the group's takeover of Gaza last week.
He ruled out talks with the Islamist group - a rival of his Fatah faction - but said the ongoing crisis should not prevent peace talks with Israel.
A Hamas leader in Lebanon, Osama Hamdan, condemned Mr Abbas' speech as "full of lies".
"It is inappropriate for any president of a people to shut the door to dialogue with an integral part of his people whose weight and size he knows full well," Mr Hamdan said.
Last week, Hamas militants seized bases and government compounds in Gaza from rivals Fatah, which Mr Abbas heads.
Mr Abbas said the takeover was a premeditated attack agreed with unspecified "foreign elements" in the region.
It was his toughest speech since the escalating violence in Gaza culminated in last week's showdown, says the BBC's Aleem Maqbool in Ramallah.
In the wake of the Gaza takeover Mr Abbas sacked the Palestinian government, led by Prime Minister Ismail Haniya of Hamas, and replaced it with an emergency cabinet.
The president said peace talks with Israel should resume despite the crisis, calling on the international community to convene a conference.
The atmosphere is not preventing a start to negotiations," he said.
He was speaking at a meeting of the Palestine Liberation Organisation (PLO), an umbrella political group, in the West Bank town of Ramallah.
"There is no dialogue with those murderous terrorists," Mr Abbas said, referring to Hamas militants.
Mr Abbas accused Hamas of trying to assassinate him during a planned visit to Gaza a month ago, saying he had seen videotapes in which militants discussed explosives that would be used to kill him.
The president said Hamas had given Israel an excuse to "punish an entire people" and warned Israel not to take advantage of the upheaval to separate Gaza from the West Bank.
After his speech, thousands of Hamas supporters demonstrated in Gaza, shouting anti-Abbas slogans and burning an effigy of him.
Separately, the European Union has said it will pay 22m euros ($30 million) of debt amassed by the Palestinian Authority to strengthen the new government.
External Relations Commissioner Benita Ferrero-Waldner told the European Parliament the EU would also continue humanitarian aid to the region - including to Gaza. The EU is one of the largest donors of aid to the region.
Earlier on Wednesday, Palestinian Information Minister Riyad al-Malki announced that all citizens would have to apply for new travel documents. The new passports would be issued in the West Bank.
It was unclear how Gazans would be able to reach the West Bank to obtain the new documents, as many are barred from travelling through Israel.
Meanwhile at least five sick Palestinians from Gaza, including a teenager with leukaemia, crossed into Israel for urgent medical treatment, Israeli officials said.
They were allowed to travel after Israeli Defence Minister Ehud Barak ordered the army to let wounded Palestinians through the Erez crossing for medical assistance.
Dozens of people have been stranded at the crossing since Hamas seized control of the Gaza Strip.
Most people fleeing have been denied entry by Israel, which controls the crossing, on security grounds.
Aid agencies were allowed to deliver food and medical supplies to Gaza, but the UN has warned of shortages within two weeks unless Israel lets normal shipments through.
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