JERUSALEM — The crisis in the Palestinian Arab territories threatened to spill across the Middle East yesterday after Egypt accused Iran of sponsoring Hamas in its takeover of Gaza and said that Tehran now posed a threat to its own national security.

The Egyptian government, which reinforced its military presence on its border with the Gaza Strip last week, said it would do everything possible to prevent an Islamist regime from cementing control of the territory.

The warning came as it was announced that President Mubarak of Egypt will host a summit on Monday attended by Prime Minister Olmert of Israel, President Abbas of the Palestinian Authority, and King Abdullah of Jordan.

Egypt’s control of its border with Gaza is likely to be a major subject for discussion, as well as the need to prop up the beleaguered administration led by Mr. Abbas and his Fatah faction from its West Bank headquarters in Ramallah. Egyptian press reported that additional Egyptian troops were moved to the border to deal with the refugee crisis. But according to Egyptian diplomatic sources, the government has rejected any suggestion of entering Gaza or accepting an international force on that border.

However. a senior official in Egypt’s ruling National Democratic Party said it would try to prevent Islamist rule.

“It is not in Egypt’s interests [to permit] presence of a religious state on its borders, and it will do its best to end such a presence,” Ali Eldin Helal said.

Ahmed Abul Gheit, the Egyptian foreign minister, said: “Iran’s policies encouraged Hamas to do what it has done in Gaza and this represents a threat for Egypt’s national security, because Gaza is a stone’s throw from Egypt.”

Egypt has moved its embassy from Gaza City to the West Bank in protest at the Hamas takeover last week.

The leaders meeting in Sharm el-Sheikh next week are united by their fear of growing Iranian influence. They are expected to offer their support to Mr. Abbas in the form of concessions from Israel.