DERA ISMAIL KHAN, Pakistan - A suspected US missile strike killed four alleged militants in a Pakistani tribal region along the Afghan border early Monday, Pakistani intelligence officials said.

The strike was the first since the arrest of an American who shot two Pakistanis in late January, and indicates Washington won't abandon the controversial tactic even as it is engaged in a dispute with Pakistan over whether the American has diplomatic immunity and should be freed.

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The two intelligence officials say three missiles hit a house overnight Monday in the Kaza Panga village of the Azam Warsak area of South Waziristan tribal region. The exact identities of the dead were not immediately clear.

The officials spoke on condition of anonymity because they are not authorized to speak to reporters on the record.

Most of the missiles hit North Waziristan, a region populated with several militant groups whose primary focus is attacking US and NATO troops across the border in Afghanistan. The Pakistani military has not taken action in that area because it says its priority is to go against militant groups launching attacks on Pakistan's soil.

Nonetheless, the US strikes do occasionally hit other parts of the tribal regions, typically South Waziristan.

The frequency of the missile strikes -- typically more than one a week -- dropped to zero after American Raymond Davis was detained for shooting two Pakistanis on Jan 27.

The US has demanded his release, arguing Davis was acting in self-defense against robbers and has diplomatic immunity from prosecution because he works for the US embassy.

The US rarely acknowledges the covert, CIA-run missile program, and it was never clear if the Davis incident had any direct impact on the lull in missile strikes. But observers have speculated the US may have been holding back to avoid further angering a population already riveted by the Davis arrest.

Pakistan's government publicly denounces the missile strikes as violations of its sovereignty, but is believed to secretly support the program. Wary of public opinion, however, Islamabad has strained its ties with the US by refusing to verify whether Davis is a diplomat. Officials here say the matter is up to the courts.