Lebanon's pro-Western prime minister rejected opposition criticism over planeloads of US military aid pouring in to shore up the country's army in its battle with Islamic militants in a Palestinian refugee camp. Meanwhile, heavy exchanges late Saturday between the army besieging the Nahr al-Bared camp near the northern port city of Tripoli and Fatah Islam militants inside punctured a four-day-old truce. Witnesses reported bursts of automatic machine gun fire, occasional rockets and artillery shots, but saw no troop movements. Earlier, a few dozen Palestinians left the camp during a lull, and some food and medicine was sent in for thousands of Palestinians trapped inside. In a videotape obtained by AP Television News in Tripoli, the head of the Fatah Islam, Shaker Youssef al-Absi, remained defiant and said his fighters would not surrender but would kill those who storm the camp. "We wish to die for the sake of God... Sunni people are the spearhead against the Zionist Americans," the bearded leader said. He was shown seated before a black banner, as another militant holding a machine gun stood next to him. The tape also showed militants training in an unidentified camp. Three US transport planes arrived from Kuwait on Saturday, according to airport officials speaking on condition of anonymity because they were not authorized to speak to the media. US arms are a sensitive issue in a nation deeply divided between supporters of Prime Minister Fuad Saniora's government and an opposition backed by America's Mideast foes, Iran and Syria. The Shiite Hizbullah-led opposition accuses Saniora of having too close ties to Washington. Hizbullah leader Sheik Hassan Nasrallah criticized the American aid, saying Friday that Lebanon was being dragged into a US war against al-Qaida that would destabilize the country, and warning the military against attacking Nahr el-Bared, where the militants have been holed up since Sunday alongside thousands of trapped Palestinians. The military has rolled more troops around the camp, which is already ringed by hundreds of soldiers, backed by artillery and tanks. Fatah Islam has claimed to have over 500 fighters with automatic weapons, mortars and rocket-propelled grenades, inside the camp. But Saniora told the Arabic-service of the British Broadcasting Crop. that the aid was not a "crime" and that the weapons had been offered by different countries a year ago. "Don't we want to protect Lebanon? Who defends Lebanon?" Saniora said, adding that Nasrallah's criticism reflected a desire to "keep the army weak in order to justify the presence of other armies" - a reference to Syria, Hizbullah's close ally whose troops controlled Lebanon for nearly three decades. Saniora discussed the situation in the camp with Palestinian President Mahmoud Abbas, Arab League Secretary-General Amr Moussa and UN Secretary-General Ban Ki-moon, the state-run National News Agency said. Karen Koning AbuZayd of the UN Relief and Works Agency for Palestinian Refugees, known as UNRWA, said after talks with Saniora that her organization would help with the "shelter and medical problem" facing the refugees. Palestinian factions have been scrambling to find a negotiated solution to end the siege and avert what many fear would be a bloody battle between the Lebanese army and the Fatah Islam. According to the National News Agency, Saniora told Abbas by telephone that the government is giving Palestinian factions time to "solve the problem of the Fatah Islam... and find a solution to their rebellion in the camp." Defense Minister Elias Murr said Friday he was "leaving room for political negotiations," which must lead to the surrender of the militants. "If the political negotiations fail, I leave it to the military command to do what is necessary." An all-out army assault could spark violence elsewhere in Lebanon, host country to some 400,000 Palestinian refugees who mostly live in camps that are rife with armed groups. The US military aid could inspire other militants into what they perceive as an all-out battle against the West. So far, eight military transport planes have landed at Beirut airport since Thursday, including four from the US Air Force, two from the United Arab Emirates and two from Jordan. Media reports said the planes carried ammunition, body armor, helmets and night-vision equipment. US military officials have said Washington will send eight planes of supplies, part of a package that had been agreed on but that the Lebanese government asked to be expedited. About half of Nahr el-Bared's population of 31,000 is estimated to have left the camp during the truce, flooding into the nearby Beddawi camp. At least 20 civilians and 30 soldiers were killed in the fighting earlier this week. The Lebanese military says 60 Fatah Islam fighters were killed, though the group put the toll at 10.