"We are in the midst of a cycle of violence that must be stopped immediately," Tor Wennesland said in a statement.

Wennesland said he was "alarmed" at the violence, which Israeli army said included soldiers launching shoulder-fired rockets amid ferocious gunfire.

"The Security Council has spoken with one voice, calling on the parties to observe calm and restraint, and to refrain from provocative actions, incitement and inflammatory rhetoric."

The call came a day after Israeli troops entered the Jenin refugee camp.

Witnesses said rockets had been fired at a building housing a group of militants, and reported gunfire in the streets elsewhere in the northern West Bank camp.

Thick plumes of smoke were seen rising from buildings, as Israeli armoured vehicles moved through the streets, according to an AFP photographer.

The Palestinian health ministry said in a statement that six men had been killed, one aged 49, and the rest in their 20s.

Sixteen others were wounded, the statement added, two of them with serious injuries.

Nabil Abu Rudeina, spokesman for Palestinian president Mahmud Abbas, called the use of rockets in Jenin refugee camp on Tuesday an act of "all-out war", Palestinian news agency Wafa reported.

The Jenin raid was the latest in a string of deadly military operations in the Palestinian territory, which Israel has occupied since the 1967 war.

"I am deeply disturbed by the continuing violence," Wennesland said, condemning both Israeli settler violence against Palestinians and Palestinian attacks against Israelis.

"Israel, as the occupying power, must ensure that the civilian population is protected and perpetrators are held to account," he said.

Commitments made by the two sides in Jordan last month, when they agreed to "commit to de-escalation", must be implemented if "we are to find a way forward", Wennesland said.

Washington, a staunch ally of Israel, was quick to denounce comments by an Israeli minister for a flashpoint Palestinian town to be "wiped out", but US State Department spokesman Ned Price adopted a more apologetic tone in a more recent statement.

"Israel, as we have made the point before, has the legitimate right to defend its people and its territory against all forms of aggression, including, of course, those from terrorist groups," Price told reporters.

The American spokesman did not express concern regarding civilian Palestinian casualties or even urge Israel to act with restraint. "We’ve said this many times before, but we continue to believe that Israelis and Palestinians deserve equal measures of freedom, of security, of prosperity. That remains our goal," he added. 

*This story was edited by Ahram Online