- Gunmen fire Friday at a North Sinai police station
- Hamas condemned Sunday's attack as an "ugly crime"
- Palestinian offshoot of Hamas probably behind the attack, Egyptian general says
- Egypt responds by sending a convoy into North Sinai
Masked gunmen on motorbikes fired early Friday at a police station in North Sinai in the latest in a string of violent acts in the area, a police official who is not authorized to speak to the media told CNN.
No one was hurt and the gunmen fled, the official said.
Al Reissa had been the scene of an hours-long battle between militants and Egyptian security forces on Wednesday, when it was one of six locations targeted by masked gunmen in a coordinated series of attacks in North Sinai in which five security officers and a civilian were wounded, according to Gen. Ahmed Bakr, head of North Sinai security.
Egyptian Army Apache helicopters fired rockets Wednesday, resulting in numerous casualties, Bakr said. State-run Nile TV reported that the strikes killed at least 20 in the port town of El Arish.
CNN has not been able to confirm the number of deaths.
Friday's attack came within hours of a meeting between scores of Bedouin leaders and Egypt's newly appointed interior minister, Ahmed Gamal Al Din, over stopping the violence.
Al Din blamed the chaos on the tunnels between Egypt and Gaza, citing them as smuggling routes for terrorists and weapons.
"All tribal chiefs of Sinai agreed to the destruction of all tunnels," tribal leader Mohamed Tarabeeni told CNN. "The minister requested the assistance of the Bedouins in securing the region and protecting the borders the same way they did during the 1967 and 1973 wars with Israel."
The developments came after 16 Egyptian soldiers were killed and seven others were wounded Sunday, when assailants with semiautomatic weapons and hand grenades stole two armored vehicles from Egyptian forces and tried to enter Israel.
Hamas condemned Sunday's attack as an "ugly crime."
An Egyptian general who works in intelligence in North Sinai told CNN, "There is a high probability that those who committed the Sunday massacre ... are members of Palestinian Islamic Jaljala Army, which is a group considered an offshoot of Hamas but with more radical beliefs."
Hamas controls the tunnels into and out of Egypt, so the attackers must have informed Hamas, the general said. And the attackers "must have received assistance from Bedouins in Sinai for logistical support, motivated by money."
The Palestinian Authority spokesman in Gaza, Tahir Al-nono, said Hamas Prime Minister Ismail Haniya, his interior minister and security leaders decided Sunday to close the tunnels from Egypt.
On the Egyptian side of the border, bulldozers and cranes were sent to block the tunnels into Gaza.
Egypt's military leadership, the Supreme Council of the Armed Forces, said 35 assailants -- terrorist factions from Gaza -- were involved in Sunday's attack near the Rafah border crossing.
Violence has spiked because jihadists in the region see "an opportunity," said Adam Raisman, a senior analyst with the SITE Intelligence Group, which monitors jihadist groups.
"They see that what they wanted from the Egyptian revolution has not come to fruition," Raisman said. "They wanted a sharia-based government." Angry with newly elected Egyptian President Mohamed Morsy for not building a fundamentalist government, jihadists are "taking advantage of the tumult in the region," the analyst said.
Morsy resigned from the Islamist Muslim Brotherhood after winning the election, promising to be a president to all.
Jihadist elements in the Sinai region express solidarity with Palestinian groups "and espouse the same beliefs and the same goals," Raisman said.
But there could be a more complicated plan behind the recent attack, according to Elliott Abrams, senior fellow for Middle Eastern studies at the Council on Foreign Relations: to drive a wedge between the new Egyptian government and the military.
The Egyptian military has been cooperating with Israel, particularly on intelligence matters involving jihadists in the Sinai. But the Muslim Brotherhood -- the dominant party in the new Egyptian government -- sees Israel as the enemy and is not comfortable with that cooperation.
As the violence spirals, the military has more reason to cooperate with Israel, angering the Brotherhood even more.
"This drives a wedge between the army and the Brotherhood," Abrams said.
But the violence presents Morsy with an opportunity, said Patrick Skinner, a senior associate with The Soufan Group, which tracks global security issues.
Since Sunday's attack did not kill Israelis, standing up against the perpetrators "will make him look stronger" to Egyptians, Skinner said. It can be "unifying."
It also "really helps his relationship with the Israelis," Skinner added.
Egypt's Supreme Council of the Armed Forces said Wednesday in a statement that the operation targeting "armed terrorist elements" in Sinai "has accomplished this task with complete success."
Sinai has long had its own identity, with many inhabitants -- particularly Bedouins -- not considering themselves Egyptians. They complain of a heavy-handed Egyptian state intruding on their terrain, providing large tracts of land to Cairo-based businessmen and investors, and failing to involve them in developing the region's prosperity.
During last year's revolution, Sinai inhabitants attacked police stations, particularly in El Arish. Security forces detained scores of Bedouins accused of involvement in a string of terrorist bombings in Sinai between 2004 and 2006.
Also, Egyptian security sources said 23,000 prisoners escaped during the revolution, and only a third have been re-apprehended. Many of those on the lam are believed to have fled to Sinai.