ISLAMABAD -- U.S. drones fired missiles at three hideouts in a key militant sanctuary close to the Afghan border Friday, killing 18 suspected insurgents in the latest of a series of strikes conducted this week despite protests from Islamabad, Pakistani intelligence officials said.

The strikes took place in the North Waziristan tribal area, the target of a planned Pakistani military operation that the United States expects soon. Hundreds of militants and their family members have left North Waziristan in the past few days in anticipation of the operation, local residents said.

Washington has long demanded Pakistan target militants holed up in North Waziristan and has welcomed the planned operation in the area. But Islamabad is likely to focus on Taliban militants who have been at war with Pakistan, not those who have been fighting the U.S.-led coalition in neighboring Afghanistan.

In a string of strikes Friday just minutes apart, U.S. missiles slammed into mud-brick compounds located several miles from each other in the Shawal Valley, a heavily forested, mountainous area in North Waziristan that serves as one of the key crossing points for militants heading into Afghanistan, Pakistani intelligence officials said.

Eighteen suspected militants were killed and another 14 were wounded, the officials said on condition of anonymity because they were not authorized to talk to the media. It was not immediately clear which militant group was hit.

The United States has carried out seven drone strikes in the past week in North Waziristan, ignoring repeated Pakistani protests that they violate the country's sovereignty and international law. The covert CIA attacks have increasingly become a point of public conflict between the two countries, complicating an already troubled relationship that is vital to the outcome of war in neighboring Afghanistan.

LI woman's accused stalker in court ... Blakeman discusses campaign priorities ... LI Works: Making stone countertops ... Westbury Gardens hosts Lego exhibit ... Get the latest news and more great videos at NewsdayTV Credit: Newsday

LI woman's accused stalker in court ... Blakeman discusses campaign priorities ... LI Works: Making stone countertops ... Westbury Gardens hosts Lego exhibit ... Get the latest news and more great videos at NewsdayTV

LI woman's accused stalker in court ... Blakeman discusses campaign priorities ... LI Works: Making stone countertops ... Westbury Gardens hosts Lego exhibit ... Get the latest news and more great videos at NewsdayTV Credit: Newsday

LI woman's accused stalker in court ... Blakeman discusses campaign priorities ... LI Works: Making stone countertops ... Westbury Gardens hosts Lego exhibit ... Get the latest news and more great videos at NewsdayTV

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