By Duncan Campbell in Beirut and Clancy Chassay in Badawi refugee camp

Lebanon’s worst internal violence for two decades is in danger of spreading throughout the country, politicians, diplomats and refugees warned yesterday, as anger grew at the tactics of the Lebanese army fighting Islamists in a northern refugee camp.

Officials representing the 400,000-strong Palestinian community in Lebanon said there was a risk of militant sympathisers in other Palestinian camps rising up, after days of clashes in and around the Nahr al-Bared camp left at least 22 militants and 32 soldiers dead, as well as a dozen civilians. Scores have been wounded.

"In the other camps, we have fundamentalists," said Souheil el-Natour, of the Democratic Front for the Liberation of Palestine. He pointed to recent armed demonstrations by a unit known as the Soldiers of the Martyrs. "They were sending a message to say what would happen [if the Lebanese army used more force].

"If the fundamentalists want to get revenge, they will go to Sidon," he added, referring to a large refugee camp in southern Lebanon which is highly symbolic as the birthplace of the assassinated prime minister Rafik Hariri.

Refugees fleeing four days of intense fighting at the Nahr al-Bared camp said anger over the Lebanese army’s indiscriminate shelling had reached boiling point, while some said sympathy was growing for the militant group Fatah al-Islam.

"The army have been killing us, they were hitting anything that moved," said 27-year-old Maher, who had left the camp the previous night for the relative sanctity of the nearby camp of Badawi. "Nobody can step out of their house without being shot at. Even inside the houses it isn’t safe from the bullets."

Abu Ali, 45, added: "We have never experienced violence like this. Not even the Israelis behaved like this."

As a shaky ceasefire held yesterday, refugees took the chance to leave Nahr al-Bared for Badawi, a camp of 45,000 refugees heaving with an influx of nearly 10,000 new residents. Outside one of three schools housing people, women sat weeping. Others stocked up on supplies, eager to get back to family members still inside Nahr al-Bared, even though renewed exchanges of gunfire last night appeared to indicate a breakdown in the truce.

Sheikh Muhammad Abu Haid, who left Nahr al-Bared on Wednesday, said there was no water or electricity, and clinics were running out of medicine. He said he watched as a teacher with the UN refugee agency UNRWA, was killed as he prayed outside the mosque, and described how his closest friend had been killed while delivering medical supplies. "He came to discuss what to do with all the dead. An hour later we had to wrap him and put him with the rest of the bodies."

Attitudes toward the militants were mixed. Aid workers said many refugees were exasperated at both sides in the conflict. But some Palestinians expressed support for the Islamist group. "They are fighters who came here to prepare for jihad against Israel and the Americans in Iraq, and we support them," said Ziad, who was shot in the leg by the army as he crossed the road.

Another Palestinian, Mazen, said: "They are peaceful people, religious, but very secretive. They were always staying in their house. No one knows where they came from."

Despite being unable to determine how the militants got into the camp, residents from Nahr al-Bared were sceptical about accusations that the fighters were manipulated by Damascus.

Yet Syria is blamed by many in Beirut for the sudden convulsions in Lebanon, a pulse of violence exacerbated this week by a succession of as yet unexplained bombings in and around Beirut. The three explosions, which killed one and injured around 30, targeted a Christian area, a Sunni area and a Druze mountain resort. A government official said that it appeared that the aim was to cause fear rather than mass casualties.

Eddy Abillama of the Lebanese Forces party, part of the government, told the Guardian: "The Syrians will continue this destabilisation, but the difference between now and the civil war is that the Lebanese are united." He said he believed the bombs were a warning from Syria not to continue with the UN tribunal to investigate the assassination of Hariri, which many Lebanese believe was coordinated by Lebanon’s larger eastern neighbour.

Last night, the Lebanese prime minister, Fouad Siniora, vowed: "We will not be intimidated by explosions and assassinations." But Walid Jumblatt, the Druze leader and MP who earlier this week accused Damascus of being behind Fatah al-Islam, said: "Unfortunately I expect that the explosions will increase."

– The Guardian (www.guardian.co.uk); May 25, 2007