By Mark Hosenball

WASHINGTON (Reuters) - U.S.-operated drones carried out deadly missile strikes against suspected al Qaeda targets in Pakistan and Yemen on Friday, U.S. government sources said.

There was no connection between the targets in the two locations, other than the fact that both sets of militants who were attacked were believed to have had some connection with al Qaeda affiliates, according to the sources.

Reports from Aden said that at least five suspected al Qaeda militants traveling in a car in southern Yemen's Shabwa province were killed when a drone strike set their vehicle on fire. Witnesses said a second drone hit an empty building.

In Miranshah, the main town in Pakistan's North Waziristan region, a drone strike killed four suspected militants and wounded three others, local intelligence officials and militants said. An intelligence official claimed the dead men were local Taliban militants.

Both drone strikes are understood to have been conducted as part of a long-running campaign intended to kill and disrupt al-Qaeda using missile-firing drones operated by the Central Intelligence Agency, which declines comment on such operations.

U.S. officials cited the latest drone attacks as a refutation of recent news reports suggesting the United States was curtailing drone operations.

One report, which U.S. officials denied, said that earlier this year, the United States had offered a suspension of drone attacks in Pakistan in connection with efforts to improve strained bilateral relations.

A U.S. official said: "The United States is conducting, and will continue to conduct, the counter terrorism operations it needs to protect the U.S. and its interests."

The official added that the United States and Pakistan were continuing to engage in "an ongoing dialogue about how best the two countries can enhance their cooperation against al Qaeda and other terrorist groups that threaten the citizens and interests of both countries."

RULES OF ENGAGEMENT

U.S. officials acknowledged the rate of drone strikes in Pakistan had declined over the past year.

For a two-month period beginning late last year, attacks were suspended, in part to ease Pakistani anger over a November border incident in which U.S. forces accidentally killed 24 Pakistani soldiers in an aerial bomb attack along a remote area of the Afghan/Pakistan border.

U.S. drone strikes in North Waziristan, where U.S. authorities believe many al Qaeda and Taliban militants take shelter, resumed in January. But the rate of attacks has remained scaled back compared to more frequent strikes which followed a loosening of the rules for targeting such attacks in the final months of the Bush administration.

Bush's new rules of engagement for drones, in which gatherings of suspected "foreign fighters" could be targeted without hard information that a "high value" militant leader was among them, remained unchanged under president Barack Obama, until relations between Washington and Islamabad started on a downward spiral in late 2010.

U.S.-Pakistan tensions continued to deteriorate following incidents like the May 2011 raid in which U.S. commandos killed Osama bin Laden at a hideout near Pakistan's principal military academy and the wayward U.S. airstrike last November.

As a consequence, in recent months the frequency of drone strikes has been noticeably scaled back. One U.S. official said that under updated procedures, more and higher-level, advance scrutiny is being given within the U.S. government before authorizations for attacks are issued.

According to a U.S. source, the latest drone attacks in Pakistan and Yemen targeted persons who could be considered as suspected members of the leadership of al Qaeda's Pakistani and Yemeni affiliates.

In neither case were the targets, whose fates are unconfirmed, figures who would be known to the general public as militant leaders, the source said.

(Editing by Warren Strobel and Todd Eastham)