The killing of an al-Qaeda leader in Saudi Arabia has dealt a "major blow" to the organization, a top Saudi official in Washington has said.
Foreign affairs adviser Adel al-Jubeir said a Saudi campaign which included the shooting of Abdul Aziz al-Muqrin had destroyed al-Qaeda's capabilities.
The group later confirmed in a statement on an Islamist Web site that Muqrin and three others were killed. It said earlier it had carried out the beheading of US hostage Paul Johnson.
It also pledged to continue what it called its holy war. "Fighting commander Abdul Aziz bin Issa al-Muqrin fell as a martyr on Friday ... in an ambush laid for him by the soldiers of tyranny in the Malaz district of Riyadh," the statement, signed by "al-Qaeda in the Arabian peninsula," said.
"The mujahedeen are continuing the jihad that they have pledged to God and the killing of their brothers will not weaken their resolve but only increase their determination and commitment," it added.
Saudi TV earlier broadcast photos of what it said was Muqrin's body. Jubeir said Saudis were "outraged" at the beheading of Johnson, an engineer who was held hostage for a week.
He added that Muqrin had been involved in the killing of BBC cameraman Simon Cumbers and the wounding of correspondent Frank Gardner earlier this month.
Saudi security forces had impounded three cars used in the BBC attack, he said.
Muqrin was killed along with three other militants in a shootout in Riyadh, Saudi officials said.
The killing of their brothers will not weaken their resolve but only increase their determination and commitment, said a statement on the militant Web site.
Witnesses said they had seen Johnson's body being dumped, but Jubeir said the body had still not been recovered. He said one of the militants killed had escaped after attacking a compound in Khobar in May which led to the deaths of 22 people. Another had been in charge of the group's logistics, he added.
Twelve other alleged militants have also been arrested in the crackdown in which one Saudi officer was killed.
There was anger at the killing in Johnson's home state of New Jersey.
"Our people have derived satisfaction that we have killed those who are responsible," said Jubeir. "We are resolved to fight terrorism, those who fund it and those who attempt to justify it."
Saudi authorities say the militants were cornered at a petrol station in Riyadh, after witnesses spotted what appeared to be them throwing Johnson's body from their car.
The al-Qaeda cell had told the Saudi government to free jailed Islamist militants by last Friday, or it would kill Johnson.
The beheading came despite pleas for mercy from Johnson's family broadcast in the Arab world.