Pakistani intelligence officials say a suspected U.S. drone strike has killed at least two people in northwestern Pakistan.

Officials say the strike Monday hit a vehicle near Mir Ali in the North Waziristan tribal area close to the Afghan border.

The identities of the men were not immediately known.

North Waziristan is home to insurgent groups, including the al-Qaida-linked Haqqani network.

There has been a dramatic increase in U.S. drone strikes in Pakistan since May.

The drone program is extremely controversial in Pakistan, where many view it as a violation of the country's sovereignty and say it often results in civilian deaths. But U.S. officials say it is vital to combating militants that threaten the United States.