JERUSALEM, NOV. 25 -- An Egyptian gunman crossed the border to Israel this morning and ambushed military and civilian vehicles along a desert road, killing four persons and wounding 26, army officials said.

Three of the Israelis killed were soldiers who were driving buses and cars along a road that runs within a few hundred yards of the Israeli-Egyptian border, north of the Red Sea port of Eilat, officials said. The fourth was the driver of a civilian passenger bus that the assailant sprayed with automatic-weapon fire after flagging it down in the road.

The gunman, who was dressed in the khaki uniform of Egyptian border police and carried a Soviet-made Kalashnikov assault rifle, was wounded when an Israeli security guard returned fire, but escaped back across the border, the army said.

Egyptian officials said a man was later arrested near the Israeli-Egyptian border crossing at Taba on suspicion of having carried out the assault. The Egyptian Middle East News Agency described the man as a conscript, and said he was being questioned.

Hours after the event, the radical Moslem group Islamic Jihad claimed responsibility in a statement issued in Amman, Jordan. The group has been waging an offensive against Israeli targets and was linked to an attack on a tourist bus carrying Israelis in Egypt last February that killed nine persons. However, Israeli military officials said tonight they had no evidence that the attacker was linked to an organization.

The assault was the most spectacular of three guerrilla operations mounted against Israeli targets in less than 24 hours.

Early Saturday evening, the Israeli navy sank a speedboat carrying at least five fighters that was heading from Lebanon toward Israel, apparently to carry out an attack. All of the guerrillas were killed, and military sources said they were believed to belong to the radical Palestinian group headed by Ahmed Jibril.

Early this morning, a woman approached an Israeli patrol in southern Lebanon and blew herself up, injuring two soldiers and a civilian passerby, officials said.

A pro-Syrian group, the Syrian Social Nationalist Party, claimed responsibility for the suicide attack, which took place within Israel's self-declared "security zone" in southern Lebanon.

The incidents continued a wave of violence that began Oct. 8, when Israeli police killed 17 Palestinians in clashes on Jerusalem's holiest site, the Temple Mount or Haram Sharif. Military officials said the latest attacks did not appear to be coordinated.

Israeli leaders reproached Egypt for not maintaining better security along the border, and demanded that the gunman be prosecuted quickly.

Egypt arrested several persons following the bus attack earlier this year, but has been slow to take formal action against them. Israel radio quoted Deputy Foreign Minister Benyamin Netanyahu as saying such incidents "contradict the formal peace treaty signed between the two countries."

In Cairo, Egyptian Foreign Minister Esmat Abdel-Meguid said the attack was regrettable and pledged that it would be investigated "in detail." A statement by the office of President Hosni Mubarak said the killings were aimed at "sabotaging relations between Egypt and Israel."

The scene of the shootings was an isolated patch of two-lane asphalt road about 15 miles northwest of Eilat.

Israeli officials said the gunman crossed the border shortly after 6 a.m., walked about 300 yards to the road, and took a position in a ditch.

Within minutes, authorities said, the gunman fired on at least five vehicles, including civilian buses. Three soldiers driving on their own were shot and killed, their vehicles stopping along the roadside nearby. Another soldier who was driving was shot and wounded, but managed to escape.

The climax to the incident occurred when a bus filled with civilian army employees drove up the road from Eilat. The Egyptian stepped to the middle of the road and signaled the bus to stop, authorities said. The driver complied, believing that he was being asked for assistance at the site of a road accident, they said.

The Egyptian then opened fire, shattering the front window of the bus and killing the driver, officials said. A number of passengers were wounded by bullets and flying glass. Officials said a security guard on the bus returned fire, wounding the Egyptian, who then turned and fled back toward the border.

One passenger on the bus said the Egyptian had put on the uniform of one of the soldiers he shot so he did not appear suspicious. "We all thought it was an accident," the passenger, David Golan, said on Israel radio.

"Across from the bus was a man in {army} uniform who was walking toward us and we were driving toward him. When he was facing us, about 80 meters {87 yards} away, he started to fire automatic fire," Golan said.

Tonight, authorities reported that seven of the wounded were hospitalized for gunshot or shrapnel wounds, while 19 were treated and released.

The multiple incidents occurred on a day when the Israeli cabinet under Prime Minister Yitzhak Shamir voted to approve a successor to the present army chief of staff, Lt. Gen. Dan Shomron.

The new chief, Israel's highest-ranking military officer, will be Gen. Ehud Barak, the current deputy chief of staff and former head of army intelligence, who was a favorite for the post.

Barak will succeed Shomron next April, when his normal four-year tour as chief of staff expires.

Barak, a native of Israel's Sephardic Jewish community, won renown as a paratrooper. He attended Stanford University as a post-graduate student. He is commonly thought to share Shomron's relatively liberal views on Israeli-Palestinian relations.