Hamas is becoming a bigger threat....

The Egyptians may no longer contain them...

Three years behind bars in Egypt made Ayman Nofal a symbol of President Hosni Mubarak's clampdown on the enemies of Israel. A week on the run turned him into a symbol of Israel's heightened insecurity in a roiling Middle East.

Grazed by sniper fire during a mass prison break, Mr. Nofal, a senior military commander in the Gaza Strip's ruling Hamas movement, said he borrowed a cellphone to mobilize a network of Palestinian and Bedouin contacts who spirited him across the Sinai Desert and back home through a dirt tunnel under the border to a hero's welcome.

"We're preparing for the next battle," Mr. Nofal said in an interview.

To Israel, his return to the Palestinian enclave is an unsettling sign that Egypt's commitment to isolating Hamas and shutting down its crossborder network is waning. That development, Israeli officials say, is the most pressing of many security threats stemming from the departure of Mr. Mubarak, the Jewish state's only reliable regional ally.

Two Israeli officials familiar with intelligence reports said this week that Hamas, emboldened by Mr. Mubarak's resignation and its own successful crackdown on popular discontent at home, had stepped up the smuggling of militants and weapons through Egypt to be stockpiled in Gaza for use against Israel.

On Friday, Hamas won high-profile backing from Cairo when the influential Islamic cleric Yussuf al-Qaradawi, speaking at a large opposition rally, urged the interim military rulers to open "dignified negotiations" with Hamas and lift a wider blockade of Gaza that Mr. Mubarak had coordinated with Israel.

Egypt's interim leadership is divided over whether to lift the blockade, according to former Egyptian officials and analysts familiar with the military's thinking. Even if the blockade holds for now, Israeli officials worry that popular sentiment in Egypt will push an elected government lift it and cool the two neighbors' 32-year-old security alliance.

"The question is what influence people like Qaradawi will have on future Egyptian governments," said a senior Israeli official. "If you have people sympathetic to Hamas sitting in the government there, that's a game changer."

Israel and Egypt imposed a land and sea blockade on Gaza after Hamas won Palestinian Authority parliamentary elections in 2006.

The Islamist movement, which Israel and the U.S. label a terrorist group, took full control of the seaside enclave in 2007 and stepped up rocket attacks on Israel's border communities.

A 23-day Israeli assault on Gaza two years ago all but stopped the rocket fire. Thanks to the Mubarak regime, Israeli officials say, the supply of rockets and other weapons sent by Iran through Egypt to Gaza slowed, although Hamas's extensive smuggling network remains intact.

The blockade has crippled Gaza's economy and confined its 1.5 million people. But so far it has failed in its ultimate aim of bringing down Hamas.

The movement has lost popularity in opinion polls and postponed elections, but a pervasive police apparatus has helped it weather the democratic ferment sweeping the region.

Wary of unrest at home, Hamas refrained from comment as Egyptians demanding Mr. Mubarak's ouster surged into Cairo's Tahrir Square. Security police summoned participants in an anti-Hamas Facebook campaign and seized their computers, then broke up the small crowds that tried to gather for an Egypt-style "dignity uprising."

The moment Egypt's protesters triumphed, however, the Hamas leadership embraced their cause as its own. Uniformed Hamas militants joined the celebratory crowds in Gaza City, firing guns into the air. Mubarak Children's Hospital, built in Gaza with Egyptian donations before Hamas's rise to power, was renamed Tahrir.

Hamas leaders say they expect a friendlier regime in Cairo, one that would abandon the blockade and Mr. Mubarak's passive support for Israeli military incursions in Gaza.

"We are going to benefit from this," Mahmoud Zahar, a senior Hamas leader and surgeon, said in an interview. "Mubarak worked as an agent for the hand of Israel and America, and that was deeply humiliating for the Egyptian people. They will have their say now, and our affairs in Gaza will count more than before."

Dr. Zahar dodged questions about Israel's allegation of stepped-up arms smuggling. "We are constantly listening to Israelis say they're going to crack down on Hamas," he said. "So what do you expect? We have to defend ourselves."