ISLAMABAD: Despite Pakistan's differences with the US over the CIA-driven drone operations in its tribal areas, two unmanned aircrafts fired four missiles on a large compound in North Waziristan on Friday, killing at least 25 people.The fresh strikes came two days after Pakistan's army chief, Gen Ashfaq Pervez Kayani, told the US military's top official, Admiral Mike Mullen, that such strikes complicated Pakistan's war against the militants. On Wednesday, Mullen also expressed his country's concern in Islamabad over the continuing links between Pakistan's main spy agency, the ISI, and militants attacking US-led forces across the border in Afghanistan.According to intelligence officials, four missiles were fired on a large compound in the town of Spinwam in North Waziristan on Friday."At least 25 people were killed in the attack, including five women and four children in a nearby house," officials said. The compound was occupied by supporters of local militant commander Hafiz Gul Bahadur.The US considers the area as safe haven for al-Qaida and Taliban militants. A similar attack in North Waziristan on March 17 killed more than 50 people, 40 of them tribal elders who had gathered to attend a tribal meeting for resolution of land dispute. Gen Kayani, in a rare public condemnation, called the attack "intolerable and unjustified".The United States has been using drone attacks to target al-Qaida-linked militants since 2004 in Pakistan's lawless tribal areas but such strikes recently became a source of concern for the country, which says civilian casualties stoke public anger and bolster support for extremists. Since the US president Barack Obama took office, the attacks had intensified in the tribal areas. More than 100 raids were reported in 2010. Many militants, including their senior leadership, have been killed in drone strikes, but hundreds of civilians have also lost their lives.