JERUSALEM (AP) – Israeli troops raided towns across the West Bank early Saturday, arresting 26 Palestinians accused of being militants a day after mounting violence left a five-month-old Mideast truce in tatters.

The army said it had arrested 16 fugitives in the southern West Bank city of Hebron, five Islamic Jihad militants in the town of Bethlehem and five Hamas militants in the northern West Bank city of Nablus, a militant stronghold.

The military has stepped up its operations against Palestinian militants in the wake of a suicide bombing and a relentless wave of rocket and mortar attacks that killed six people this week.

On Friday, Israeli aircraft conducted repeated strikes on militant targets, killing six Hamas militants in attacks on a West Bank militant hideout and a van filled with homemade rockets.

The violence threatened to intensify. Israeli troops massed at two makeshift camps outside Gaza, and Defense Minister Shaul Mofaz told army commanders late Friday to plan for a ground operation in northern Gaza.

Hamas threatened to avenge the airstrikes, which appeared to signal Israel’s resumption of targeted killings of militant leaders.

The fighting jeopardized the cease-fire deal Israeli Prime Minister Ariel Sharon and Palestinian leader Mahmoud Abbas reached at a February summit in Egypt, which led to a marked decrease in violence and helped Abbas fend off Israeli demands for a crackdown on the militant groups.

But the new violence called into question Abbas’ policy of trying to persuade militants to end their attacks voluntarily, and Israel and the United States were pressing him to take on the armed groups.

Early Friday, Palestinian police, trying to stop the rocket firing, fought Hamas gunmen in the streets of Gaza City, a battle that left two teens dead and 25 others wounded in the worst internal fighting among Palestinians in recent years.

Palestinian security chief Nasser Yousef said his forces will “not hesitate” to restore law and order, and ordered rocket attacks to be stopped by all means. However, the militants continued attacking Israeli targets throughout the day, launching dozens of mortar shells and rockets from across the Gaza Strip.

The Israeli airstrikes Friday afternoon were a sign that Israel had run out of patience with Abbas.

“We are taking these measures to stop these attacks as the Palestinian Authority refuses to do so,” said a statement from Sharon’s office.

Israeli aircraft targeted Hamas militants hiding out in caves about two miles from the West Bank town of Salfit, killing one militant and wounding another, the military said. Troops on the ground then went into the area and killed a surviving militant who fired at them with an automatic weapon.

Clashes between the army and stone-throwing protesters later broke out and a 16-year-old Palestinian boy was wounded by a gunshot to the head, hospital officials said.

Soon after the first airstrike, Israeli aircraft destroyed a van carrying a group of militants and a cache of homemade rockets as it raced through a Gaza City street, killing four Hamas militants, the army and Palestinian officials said.

The army said the airstrike targeted senior Hamas weapons makers on their way to launching more rockets at Israeli targets.

Israel launched another wave of airstrikes late Friday and early Saturday. One targeted a group of militants in the southern Gaza town of Khan Younis, the army said. Hamas said one of its fighters was wounded. Another strike targeted militants trying to launch rockets in the northern Gaza town of Beit Hanoun, the military said. Witnesses said the militants escaped unharmed.

Two early morning strikes in Gaza City and a third in Khan Younis were aimed at buildings Hamas used to make weapons, the army said. One of the missiles hit near a garage and a United Nations food warehouse in the Shati refugee camp in Gaza City, slightly wounding a man and a girl, hospital officials said.

Saeb Erekat, a Palestinian negotiator, condemned the airstrikes and said they were counterproductive.

“It comes at a time when we are trying to maintain the rule of law and the (unity) of our authority, and the only thing these Israeli escalations and attacks will lead to is to undermine our ability to do so,” he said.

Hamas promised to retaliate and blamed Israel for starting the violence. Earlier this week, a Palestinian police officer and a militant were killed by army fire. Those army raids came after an Islamic Jihad suicide bomber killed five Israelis in an attack in the coastal city of Netanya.

The violence Friday followed a rocket attack Thursday that killed an Israeli woman at Nativ Haasara, a communal farm just outside Gaza.

In firing rockets and mortars, Hamas was also sending a message to Abbas, underscoring their demands to share power in Gaza after Israel withdraws next month.

AP-ES-07-16-05 0425EDT