In a strongly worded message to the United States, Israel has complained that the weapons smuggling and entry of militants from Egypt into the Gaza Strip is posing a direct threat to the Annapolis conference actually taking place.

Senior Israeli political figures said yesterday that in talks with their American counterparts, they stressed that the porous border in Sinai "is becoming a strategic problem" and asked them to raise the issue with the Egyptians.

"The smuggling of weapons and terrorist experts from Sinai to the Gaza Strip through the Philadelphi Route poses a real threat to the holding of the Annapolis conference," the message read.

The Israelis also expressed their frustration about Egyptian behavior vis-a-vis Hamas, both in terms of the ease of smuggling and also politically, in view of Cairo's calls for Fatah and Hamas to renew negotiations for a unity government.

"Egypt is working against everything we are all trying to achieve," senior Israeli officials told the Americans. "We are organizing a summit to further the diplomatic process under the banner 'strengthening Abu Mazen' [Palestinian Chairman Mahmoud Abbas], and they are strengthening Hamas."

Israeli political and defense officials have expressed grave concern about developments along the Philadelphi Route on the border between the Gaza Strip and Sinai in recent weeks. They are particularly irate at the clandestine entry of dozens of Hamas militants through the border near Rafah, without Egypt's trying to stop them.

Exacerbating these concerns are reports that Islamic Jihad militants have also managed to return to the Gaza Strip from Egypt without any difficulty.

Israeli political sources said Israel has asked Egypt for clarification on both matters, and received excuses and blurred responses.

"The Egyptians are saying they [the militants] entered the Strip through a hole in the fence," an Israeli political source said.

In its message to Washington, Israel emphasized it "views with grave concern the continued strengthening of Hamas through the smuggling of weapons."

Israeli officials told the Americans that "the smuggling is taking place to undermine the general effort to restart the diplomatic process."

One of the scenarios the Israelis presented to the Americans raises the possibility that rockets will be smuggled into the Strip and launched against Israeli urban centers, causing many casualties. This would necessitate a military operation in the Gaza Strip.

"Such a situation could result in the dismantling of the international summit," the Israeli sources said.

U.S. Secretary of State Condoleezza Rice is scheduled to arrive in the region on Sunday. Rice will travel to Cairo for talks after meetings in Israel.

Israel asked the U.S. to urge Egypt to do more in its efforts to stem the flow of smuggled weapons. Americans officials have said they "also recognize the significance of this matter and we will raise it once more."

During her visit Rice is expected to focus on preparation for the summit at Annapolis, and will hold a series of meetings in Jerusalem and Ramallah with Prime Minister Ehud Olmert and Abbas.

In a related development, Minister for Strategic Issues Avigdor Lieberman met yesterday with the Quartet's Middle East envoy, former British prime minister Tony Blair. Lieberman told Blair: "Any attempt to deal with the core issues [borders, refugees, Jerusalem] at the Annapolis conference will result in the breakup of the coalition and the government in Israel." Lieberman, the leader of Yisrael Beiteinu, stressed that the solution to the Israeli-Palestinian conflict "must include the Israeli Arabs, in which the basis for a settlement is the exchange of territory and populations."

Lieberman added, "The international community must focus its efforts on the issue of Israel's security and the Palestinians' economy."