GAZA CITY Ñ Hamas has launched deadly attacks against Israeli civilian and military targets.

Hamas gunners fired three Kassam-class short-range missiles that fell in several areas of the Israeli city of Sderot on Monday. Two people standing outside a kindergarten were killed, the first Israeli casualties from a Palestinian missile fired from the Gaza Strip. Eleven other people were injured, one of them seriously.

Several hours later, Hamas fired a fourth Kassam missile toward Sderot. Nobody was injured.

Israeli officials said that the missiles that landed in and around Sderot appeared to be more powerful than the Kassams that had struck the city before June 2004. Last week, a Fatah-dominated insurgency group in Gaza City reported a new missile fired toward Sderot, termed the Nasser-3. Hamas claimed responsibility for Monday's missile strike.

"We have been struck by a missile that is different in structure [from the Kassam] and with different warhead and accuracy," Yossi Cohen, a spokesman for the Sderot municipality, said. "Today, it is Sderot. Tomorrow, it is Askhelon. Today, it is a more advanced missile. Tomorrow, it could be an even more advanced missile."

On late Sunday, Israeli attack helicopters fired missiles toward two suspected Kassam production facilities in Gaza City. An Israeli military statement said the two facilities were recently established and operated in wake of a military operation against weapons workshops in Gaza City in May.

Officials said that by late Monday Israel's military would launch another operation against Hamas gunners and Kassam missiles deployed in the northern Gaza Strip.

On late Sunday, an Israeli soldier was killed and five others were injured when Hamas blew up an Israeli military outpost in the central Gaza Strip. The outpost, termed Orhan, was destroyed by an explosion from a tunnel dug underneath the military facility.

Israeli military sources said the tunnel was dug to a depth of between 10 to 15 meters. The sources said the bomb was detonated via a cellular phone.

The Al Aqsa Martyrs Brigade and Hamas claimed responsibility for the attack. They attributed the attack to the detonation of a tunnel that stemmed from nearby Khan Yunis. Hamas released a video that showed Palestinians digging the tunnel, packing the tunnel with one ton of explosives and then detonating the charge.

Brig. Gen. Shmuel Zakai, commander of Israeli forces in the Gaza Strip, said the tunnel was constructed by Palestinian insurgents several days ago.

Zakai said the tunnel was filled with hundreds of kilograms of explosives.

"They do this in stages," Zakai said. "It's doubtful that you could detect digging at such a depth."

For weeks, the sources said, the Israeli military had been alerted to the prospect of a tunnel being built underneath an Israeli outpost. The sources said this was the second time a tunnel filled with explosives succeeded in incurring Israeli military casualties. In October 2001, an Israeli outpost along the Egyptian border was destroyed in an explosion.

In May, Israel's military launched an operation to destroy weapons and explosives tunnels along the Egypt-Gaza border. Over the last few months, the sources said, the military has reinforced outposts from car bombs and other weapons.