Security forces raided a camp used by militants blamed for the Mumbai attacks and arrested more than a dozen people in Pakistan's first known response to the assault, militants and an intelligence official said Monday. The identities of those arrested was not immediately known, but Dawn newspaper reported one of them was Zaki-ur-Rehman Lakhvi, an alleged militant named by India as one of the masterminds of the attacks on Mumbai. US and Indian suspicions that Pakistan-based militants carried out and plotted the attacks have sharply raised tensions between South Asia's only nuclear-armed nations. Pakistan's civilian government is under intense international pressure to crack down on the extremists and demonstrate they have no links to its shadowy intelligence agencies. New Delhi says the Mumbai siege was carried out and plotted by militants belonging to Laskhar-e-Taiba, a Pakistani group accused of other attacks on Indian soil. US Secretary of State Condoleezza Rice said Sunday there was "no doubt" that the attacks were planned on Pakistani soil. Troops exchanged fire with suspected extremists during Sunday's raid on the camp close to the town of Muzaffarabad in the Pakistani part of the disputed Kashmir region, two militants said. A senior intelligence official said a helicopter was used in the raid, He said more than 12 detainees were being questioned over any possible links to the Mumbai attacks and several injured people were being treated at a military hospital. He spoke on condition of anonymity because of the sensitive nature of his job. The militants said the camp was used until 2004 by Laskhar-e-Taiba to train recruits to fight Indian rule in its section of the Kashmir. More recently, it was used by Lashkar's parent organization Jamaat-ud-Dawa for education and charity work, they said. The militants declined to give their names because they belong to an illegal organization. Analysts say Lashkar-e-Taiba was created with the help of Pakistan's intelligence agencies in the 1980s to act as a proxy fighting force in Indian Kashmir. Many suspect elements within the agencies keep some links with Lashkar and other militants in the country, either to use against India or in neighboring Afghanistan. The New York Times, citing unidentified American intelligence and counterterrorism officials, reported in a story published Monday that Lashkar has gained strength in recent years with the help of Pakistan's spy service, the Directorate for Inter-Services Intelligence. The officials cited by the Times say the ISI has shared intelligence to and provided protection for the outlawed group, though there is no evidence to link the spy service to the Mumbai attacks. Islamabad's young civilian government has denied any of its state agencies were involved in the Mumbai attacks, but said it was possible that the militants were Pakistanis. It has pledged to cooperate with India, noting it too is a victim of terrorism. Pakistan and India have fought three wars over the last 60 years, two over Kashmir. In 2001, an attack by suspected Lashkar-e-Taiba militants on the parliament building in New Delhi brought the countries close to conflict. Pakistan has experienced a surge in militant violence since it sided with the United States after the Sept. 11 attacks. As part of the alliance, it allows NATO and America to truck supplies to their forces in Afghanistan through the country. Early Monday, militants in the northwestern city of Peshawar attacked a terminal for the supply trucks, torching scores of military vehicles waiting shipment, a witness and an Associated Press reporter said. The attack was the second in as many days on the supply line in the city, showing its vulnerability to militants that control large swaths Pakistan's lawless regions close to Afghanistan. Terminal laborer Altaf Hussain says several militants stormed the Bilal terminal, firing grenades. They then set fire to up to 50 military vehicles awaiting shipment, he said. It and other terminals in the city employ lightly armed security guards, aimed more at preventing theft than organized militant assaults, Up to 75 percent of the fuel, food and other logistical goods for Western forces battling Taliban insurgents in Afghanistan currently pass through Pakistan. NATO officials say the attacks on the supply line do not affect their operations in Afghanistan, but acknowledge they are looking for other supply routes to the country.