Story highlights Pentagon spokesman: U.S. used manned, unmanned aircraft in Somalia attack

It was launched based on "actionable intelligence," targeted group's leader, he says

No details on whether Al-Shabaab leader Ahmed Abdi Godane is dead or alive

The U.S. has targeted Al-Shabaab leaders in Somalia at least twice in the past year

The U.S. military went into Somalia with one goal in mind: Kill Ahmed Abdi Godane, the leader of Al-Shabaab.

One day later, Pentagon spokesman Rear Adm. John Kirby said flatly, "We certainly believe that we hit what we were aiming at."

What he did not say is whether Godane is dead.

The United States is "assessing the effectiveness right now" of the attack launched hours earlier, Kirby said Tuesday, including who, if anyone, was killed.

He did acknowledge that U.S. Special Operations forces flew aircraft that, along with unmanned aircraft, "destroyed an encampment and a vehicle using several Hellfire missiles and laser-guided missiles." No American troops were on the ground.

The attack was directed at Al-Shabaab and, specifically, its leader Godane. He has headed the network as it has terrorized East Africa, killing Somali officials, aid workers and others in a spate of suicide bombings. Godane allegedly was behind 2013's brazen, ghastly siege of a Nairobi, Kenya, shopping mall.

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It's not just what Godane, who has pledged his group's allegiance to al Qaeda, has done that made him a target. It's what Al-Shabaab was planning to bring through more bloodshed, chaos and terror to the region.

The U.S. government can't say yet whether Godane survived the attack in south-central Somalia.

But if he did not, Kirby surmised, East Africa is now a safer, better place.

"If he was killed, this is a very significant blow to their network, to their organization," the Pentagon spokesman said, "and we believe their ability to continue to conduct terror attacks."

An Al-Shababb Twitter account said one person was killed in the attack, but it wasn't Godane.

"'Ahmed Abdi Godane' is alive and doing fine," the tweet from HSM Press Office said, calling itself an "official mujahedin account" in the Islamic land of Somalia.

CNN was unable to verify the authenticity of the report.

Somali official: 'Never heard such a huge ... blast'

Tipped off by what Kirby called "actionable intelligence ... strong enough" to suggest Godane's whereabouts, U.S. commandos flew -- aided by drones overhead -- into an area south of the African nation's capital Mogadishu around 6:20 p.m. (11:20 a.m. ET) Monday.

Lower Shabelle Gov. Abdikadir Mohamed Nur Sidii characterized the attack near the port city of Barawe as so ferocious. "It jolted the entire region."

"I never heard such a huge and deafening blast as the result of the airstrike," Sidii said.

Kirby didn't elaborate on exactly how much firepower was used, beyond that there were multiple Hellfire and laser-guided missiles. Somali intelligence officials counted at least four such missiles.

The targets were what the Pentagon spokesman described as "an encampment" and a vehicle inside it, not to mention Al-Shabaab leaders believed to be there.

Kirby said that he expects the attack -- like others U.S. forces have conducted against terror groups -- sends a message.

"The operation that we've conducted, we believe, is an example of the U.S. government and our allies and partners' commitment to the people and the government of Somalia," he said, "to detect, deter, disrupt and defeat violent extremists who threaten progress in the region, as well as threaten to conduct terrorist attacks against innocent people around the world."

To figure out if the operation achieved its goals, the U.S. military will need help.

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That's because, Kirby explained, no American forces were on the ground before or after the mission.

He didn't specify who would get to the bottom of what happened, saying simply, "We continue to work with partners in the region."

U.S. has gone after Al-Shabaab before

The United States has previously gone after Al-Shabaab in Somalia. That includes at least two strikes this past year ordered by President Barack Obama's administration.

That's part of a long-running, multinational effort targeting the group, including an operation launched last week to cut off the group's supply lines along the Somali coast.

Al-Shabaab has been on the defensive of late. Its militants have started to withdraw from the port city of Barawe in recent days. On Monday, the African Union Mission in Somalia announced that military forces had retaken several important towns in the Middle Shabelle and Hiiran regions.

But no one is counting Al-Shabaab out quite yet.

The group has shown its audacity and violent ways before. It has been blamed, and taken responsibility, for attacks on city streets, at markets, at prisons and a United Nations compound in Mogadishu.

It's most high-profile attack came last year at Nairobi's upscale Westgate mall, when terrorists casually walked into the mall, pulled out weapons and began gunning down shoppers. The gunmen were accused of torturing some hostages before killing them.

As many as 67 people died in the siege, and parts of the mall were destroyed.

That and many of these other attacks occurred under Godane's watch.

If he's now gone, CNN terrorism analyst Paul Cruickshank said, it would be a serious blow to Al-Shabaab.

"Ahmed Godane is a very ruthless figure in the group, he dominates the group," Cruickshank said. "You could see a kind of leadership struggle emerge if, indeed, he was killed."

But it wouldn't necessarily be a fatal one. Godane rose to power in 2008, after all, when a U.S. airstrike killed then-leader Aden Hashi Ayrow.

"It's a network, and we understand that," Kirby said Tuesday. "We are mindful that there remain other leaders of the organization, at large."