NATO said a coalition bomb misfired into a residential neighborhood of Tripoli early Sunday and killed civilians, an acknowledgment that is likely to fuel a growing controversy over the West’s protracted effort to oust Moammar Gaddafi.

Libyan officials said the blast flattened a two-story house, killing two children and seven adults. Sunday’s bombing marked the first time NATO has acknowledged that a military mishap had resulted in civilian deaths in Libya, and it came a day after the alliance confirmed that last week it accidentally struck a vehicle carrying allied rebel fighters.

The two incidents underscored the perils of a military campaign the West is waging almost exclusively from the air, with shifting front lines and scattered allies with whom it has spotty lines of communication.

“NATO regrets the loss of innocent civilian lives and takes great care in conducting strikes against a regime determined to use violence against its own citizens,” Lt. Gen. Charles Bouchard, the Canadian commander of the alliance’s mission in Libya, said in a statement issued late Sunday.

NATO said that it intended to strike a military missile site but that “a weapons system failure” appeared to “have caused a number of civilian casualties.”

High-profile cases in which civilians were killed by U.S. and allied troops in the Iraq and Afghanistan wars became major turning points in those conflicts as anti-Western sentiment soared. And Sunday’s incident bolstered Gaddafi’s claim that the coalition’s operation is just the West’s latest bid to invade and pilfer a Muslim nation.

“We will never forgive, we will never forget,” Libyan Foreign Minister Abdul Ati al-Obeidi told reporters Sunday afternoon. He said the recent NATO bombings ought to “ignite a global jihad against the oppressive, criminal West.”

The Libya operation’s growing number of critics on Capitol Hill and in NATO capitals are certain to pounce on the incident to argue that the costly, three-month mission is foundering. The Obama administration has struggled to defend its stance that the U.S. role does not require congressional approval, while NATO is facing mounting questions about the pace and achievements of a campaign that Western leaders hoped would end within weeks.

Sunday marked the 90th day of the campaign, and Congress is likely to vote this week on amendments that would cut off funds for the operation or place restrictions on the use of U.S. troops.

“One hopes it will encourage NATO and Western governments to reconsider the case for a cease-fire, which they appear to have ignored until now,” said Hugh Roberts, a Libya expert at the International Crisis Group. “The great danger is that out of laziness, politicians will continue to succumb to the false argument that there is no alternative to military intervention.”

On Sunday, a spokesman for Sen. Richard G. Lugar (Ind.), the top Republican on the Foreign Relations Committee, said this incident brought to mind something the senator had said previously.

When “a president conducts a misdirected war, there will be misdirected results,” Mark Helmke said. He added: “Historians may look back and say, this [is] when the United States under Obama killed NATO, the most successful military alliance in history.”

The bomb struck a home in the Souk Jouma district of northern Tripoli, an area of the city where many despise the Gaddafi regime.

The streets of Souk Jouma have been restive in recent weeks. Regime loyalists have painted over anti-Gaddafi graffiti and residents attempting to stage anti-government demonstrations have exchanged gunfire with government forces, residents said in interviews Sunday.

By taking foreign journalists to the flattened house twice Sunday morning, Libyan government officials provided reporters with a rare glimpse of a side of Tripoli they have worked arduously to conceal.

Residents didn’t chant pro-Gaddafi slogans when they saw foreign journalists, as often happens in other parts of the capital. There were no photos of the autocrat, and none of the green flags used to convey loyalty to the regime were visible.

A 38-year-old man who asked to be identified only by his first name, Ali, said more than half of the area’s residents oppose the regime.

“But there is no army here,” he said, standing on a pile of rubble. “Just civilians.”

Libyan government officials have struggled in recent weeks to convince journalists that NATO has bombed civilian targets, but the accounts and evidence they have presented have often been unconvincing.

NATO aircraft have conducted more than 4,000 flights to identify or strike targets since it took command of the mission on March 31.

The bombings have destroyed critical government facilities, including Gaddafi’s palace.

In a video statement late Sunday, Wing Cmdr. Mike Bracken, a NATO spokesman, said, “The Gaddafi regime could put a stop to this fighting if it were to comply with the international community’s demands.”

But Gaddafi has vowed to defeat the alliance and has sought to portray the rebels as armed gangs collaborating with “crusaders” from the West. In a speech Friday, he urged NATO to use nuclear bombs, saying Libyans would prevail no matter what.

Others in his government have called for an immediate halt to the bombings, saying negotiations with rebels based in the western city of Benghazi might be possible if NATO suspends its mission.

Government spokesman Mous­sa Ibrahim on Sunday said the strikes against civilians were deliberate.

“They want to plant horror and terror in the heart of people so they will want a quick end to the conflict,” he said. “This is making the enemy even clearer: the West attacking a Muslim country for oil, dominance and occupation.”

Staff writer David A. Fahrenthold in Washington contributed to this report.