DERA ISMAIL KHAN, Pakistan - A suicide bomber attacked an army convoy in Pakistan's militant-plagued northwest Saturday and casualties were feared, an army spokesman said.

Pakistani media and two local intelligence officials reported up to 10 soldiers had died, but Maj. Murad Khan said he had no confirmation on exact casualty figures. The intelligence officials spoke on condition of anonymity because they were not authorized to speak to media.

The army spokesman said the attack targeted a convoy headed to Miran Shah, the main town in North Waziristan, part of Pakistan's tribal belt bordering Afghanistan.

The U.S. says the semi-autonomous tribal regions have become bases for Taliban and al-Qaida fighters involved in attacks on American and NATO forces in Afghanistan.

Washington has pressured Pakistan to crack down on extremism in the areas and has even staged unilateral operations on Pakistani territory, which have angered the Muslim nation.

The Pakistan-U.S. relationship was expected to be a focus of a key speech to parliament by newly elected Pakistani President Asif Ali Zardari later Saturday.

Pakistan has said it is doing its best to fulfill its role in the war on terror, deploying more than 100,000 troops along its northwest to flush out militants.

The country also is staging two major military operations in the northwest, including one in the Bajur tribal region that has killed hundreds of suspected militants.

Government official Iqbal Khattak said nine more alleged militants died Saturday in the Bajur offensive. The previous day also witnessed the deaths of nine suspected militants, according to Khan, the army spokesman.

Although no one immediately claimed responsibility for Saturday's suicide attack, the Pakistani Taliban have said they were behind a string of suicide bombings in the past few weeks in revenge for the military offensives.