MISGAV, Israel (Reuters) – The Israeli army moved a crane back into a tense frontier zone with Lebanon on Wednesday to complete a tree-pruning mission that led to the deadliest violence along the border since a 2006 war.

A day after a senior Israeli officer, two Lebanese soldiers and a Lebanese journalist were killed in a rare clash between the Israeli and Lebanese armies, Israel appeared keen to show it would not be deterred from operating in the area.

“We are continuing to operate. It will not be legitimate if they try to disrupt today, and we will have to respond,” Israeli Defense Minister Ehud Barak said on Israel Radio.

The United States and the United Nations urged both sides to show restraint amid fears of wider conflict, and the border zone fell quiet.

Lebanon’s Hezbollah group, which battled Israel in the 2006 conflict, stayed out of the fighting on Tuesday. It began after an Israeli mechanical arm reached over a frontier fence to trim a tree whose branches, Israel’s military said, were tripping anti-infiltration devices.

Israel said its soldiers were operating within Israeli territory and the tree was south of a border line drawn by the United Nations after the Israeli military’s 2000 withdrawal from south Lebanon. Lebanon said the tree was inside its territory.

A U.N. peacekeeping force that patrols southern Lebanon said one of its technical teams would try on Wednesday to determine exactly where the border line runs in the area.

Returning to the site of the clash, an Israeli crane, guarded by soldiers, cut down three trees, witnesses said.

Lebanese troops deployed at a distance from the fence and peacekeepers from the U.N. force known as UNIFIL patrolled the Lebanese border village of Adaisseh.

SECURITY CABINET

Sayyed Hassan Nasrallah, leader of Iranian- and Syrian-backed Hezbollah, said he did not think Tuesday’s violence would lead to a bigger conflict, “but there are reasons for worry.”

He said Hezbollah would not stand silent if Israel attacked the Lebanese army in the future.

Israeli Prime Minister Benjamin Netanyahu convened his security cabinet as both sides prepared to bury their dead. He said after the clash Israel would “respond aggressively” to any future attempt “to disrupt the calm along the northern border.”

In the Gaza Strip, where there has been an upsurge of violence over the past week, Israeli fire killed a Palestinian militant and wounded another. The Israeli military said aircraft had fired at Palestinians who approached the Gaza border fence.

The United States, Israel’s main backer, called for both Israel and Lebanon to exercise restraint.

“The last thing that we want to see is that this incident expand into something more significant,” State Department spokesman P.J. Crowley said in Washington.

The U.N. Security Council also voiced concern.

Tuesday’s deaths were the first on either side since the 2006 war in which 1,200 people, mostly civilians, were killed in Lebanon, along with 158 Israelis, mostly soldiers.

A new war could be more devastating than the last. Tension has increased since April, when Israel accused Syria of transferring long-range Scud missiles to Hezbollah in southern Lebanon — an allegation Syria has rejected.

Israel has threatened to attack Lebanese infrastructure in any new conflict. In 2006 it bombed bridges, fuel tanks, radar stations and Beirut airport, while Hezbollah fired 4,000 rockets into Israel.