An American missile strike killed a ranking member of the militant Haqqani network on Thursday in northwestern Pakistan, striking at a group that Washington claims is the No. 1 threat in Afghanistan and is supported by Pakistani security forces, local intelligence officials said.

Two other militants were killed in the attack close in the Haqqani stronghold of North Waziristan, the group's main sanctuary along the Afghan border, said the Pakistani officials in the region.

The officials spoke on condition of anonymity because they were not authorized to speak to the media.

They identified the Haqqani member as Jalil and said he was a 'coordinator' for the group. The men were walking down a street when the drone-fired missile hit, the officials said. One said Jalil was related to Sirajuddin Haqqani, the leader of the network.

The missiles hit close to Dande Darpa Khel village, which is home to a large seminary with links to the Haqqanis.

The al-Qaida-allied Haqqani network is one of most organized insurgent factions fighting the U.S. presence in Afghanistan, and it has been blamed for high-profile assaults against Western and Afghan targets in the Afghan capital, Kabul.

Washington has long urged Islamabad to attack the fighters, who live undisturbed in North Waziristan despite the region being home to several thousand Pakistani troops.

At the same time, the U.S. is pursuing the possibility of peace talks with the Haqqanis and other Taliban factions, reflecting the fact that the insurgency can't be defeated militarily.

Thursday's attack took place hours before U.S. special envoy to Afghanistan and Pakistan Marc Grossman arrived in Pakistan for talks with the country's prime minister and army chief. Grossman, whose mission is to promote the peace process, will likely discuss U.S. concerns about the Haqqani network.

Last month, senior American officials accused Pakistan's spy agency of assisting the Haqqani network in attacks on Western targets in Afghanistan, including a strike last month on the U.S. Embassy in Kabul. Pakistani officials have denied the charges.

They were the most serious allegations yet of Pakistani duplicity in the 10-year war in Afghanistan and sent already strained ties between Islamabad and Washington plunging further. Obama administration officials have since backtracked somewhat on the claims.

Most independent analysts say Pakistan is either tolerating or supporting the Haqqani network to some degree because it foresees chaos in Afghanistan once America withdraws, and wants to cultivate the group as an ally there against the influence of India, its regional enemy.

Since 2008, the United States has regularly unleashed unmanned drone-fired missiles against militants in the border region, which is home to Pakistani militants, Afghan factions like the Haqqanis and al-Qaida operatives from around the world, especially the Middle East.

This year, there have been around 50 drone strikes, most of them in North Waziristan. U.S. officials do not acknowledge the CIA-led program publicly.

Pakistani officials protest the strikes, which are unpopular among many Pakistanis, but the country is believed to support them privately and makes no diplomatic or military efforts to stop them.

U.S. leverage against Pakistan to get it to fight the Haqqani group is limited because it relies on the country to truck much of its war supplies into Afghanistan.

The supplies of non-lethal material arrive in Pakistan's port of Karachi by sea before traveling into Afghanistan by land.

The convoys are occasionally attacked by insurgents, especiallty close to the border, where the militants are strongest.

On Thursday, gunmen opened fire and set ablaze five tankers carrying oil for NATO and U.S. troops in Sindh province, some 1,200 miles (2,000 kilometers) from the border, said police officer Khair Mohammad Samejho.

The tankers were parked outside a restaurant in Shikarpur district when they were attacked, he said.