WASHINGTON (CNN) -- Investigators were studying an explosive device Tuesday that they say terrorists in Yemen crafted to slip past airport metal detectors and onto an airplane bound for the United States.
U.S. intelligence agents thwarted the plot two weeks ago after receiving a tip from Saudi Arabia, a source familiar with the operation said Tuesday. Authorities have said airline passengers were never in danger and that the would-be bomber no longer poses a threat.
Even so, the plot highlights the resolve of terrorists to attack the United States a year after the U.S. military killed Osama bin Laden in a stunning raid inside Pakistan.
It also shows the lengths they will go to to achieve that goal, adapting new technologies to try to evade security, as well as the difficulties that U.S. authorities face in trying to guard against attack, said Rep. Peter King, chairman of the House Intelligence Committee.
"This seems to be a new level of sophistication by al Qaeda," King told CNN's "Starting Point."
King also said activities surrounding the bomb plot are linked to Sunday's death of Fahd al Quso, a senior operative of al Qaeda in the Arabian Peninsula, in a U.S. drone strike in Yemen, King said.
"I was told by the White House they are connected, they're part of the same operation, and that's why I said this operation is still ongoing," he said.
He did not provide further details.
U.S. officials were confident they were in control of the situation leading up to the seizure of the improvised explosive device, or IED, John Brennan, the chief White House counterterrorism adviser, said on ABC's "Good Morning America."
"Now we're trying to make sure that we take the measures that we need to prevent any other type of IED, similarly constructed, from getting through security procedures," Brennan said.
On Monday, officials said U.S. and other intelligence agencies had seized the explosive device, which they said was similar to ones previously used by al Qaeda in the Arabian Peninsula. Western officials describe that group as al Qaeda's most dangerous affiliate, the FBI said.
U.S. officials believe the al Qaeda affiliate has more than 1,000 members in Yemen and connections to al Qaeda leadership in Pakistan.
Yemini authorities appeared miffed by the revelations, saying Tuesday that Washington had not shared any information.
"Yemen has been a key ally to the United States when it comes to fighting terror and cooperates in every way possible," said a senior intelligence official in Yemen who asked not to be named because of the sensitivity of the situation. "It's very sad to know that the United States did not share such critical intelligence information with Yemen.
"The United States cannot win the war on terror alone, and intelligence sharing must be bilateral if it expects complete cooperation from Yemen," the official said.
The plot was discovered before it threatened any Americans, and no airliners were at risk, one U.S. counterterrorism official said. A nonmetallic explosive device such as the one used in the failed attempt to bomb a Detroit-bound jet in 2009 was recovered, the official said, adding it was meant for use by a suicide bomber.
A Department of Homeland Security spokesman said authorities have "no specific, credible information regarding an active terrorist plot against the U.S. at this time," although they continue to monitor efforts to carry out such attacks.
President Barack Obama was told about the plot in April, and the attempt "underscores the necessity of remaining vigilant against terrorism here and abroad," the White House said.
The threat was foiled around the same time as the anniversary of the raid that killed bin Laden, although a second U.S. counterterrorism official said the attempted attack was not timed to coincide with the death of the al Qaeda leader.
The FBI said it is conducting technical and forensic analysis on the improvised explosive device.
King, the New York Republican lawmaker, said discovery of the bomb plot is just one part of an ongoing operation.
"It's not over as far as the operation itself, which is why you're seeing very few details being given out," he said.
Both King and a senior administration official said the intended user of the bomb is no longer a threat.
CNN national security contributor Frances Townsend said that doesn't necessarily mean the would-be bomber is dead.
"He's in custody wherever that device was seized," she said.
The recovered device, which never made it near an airport or airplane, was not built to be a so-called body bomb, the official said.
Al Qaeda in the Arabian Peninsula "is the responsible group here," a different senior U.S. official said.
"While similar, a preliminary review of this device shows that it has some significant differences from the device used in the Christmas Day attack. It is clear that AQAP is revamping its bomb techniques to try to avoid the causes of the failure of the 2009 device," the official said, referring to the Detroit incident.
The Yemen affiliate of al Qaeda has been behind two of the most audacious attempts to target the United States in recent years: the attempted 2009 bombing and the printer bombs loaded onto cargo planes in 2010 and destined for an address in Chicago.
In both cases, U.S. authorities believe the bombs were built by Ibrahim al-Asiri. Both devices contained a main charge of PETN, a white powdery explosive that conventional "single beam" X-ray machines are rarely able to detect.
In 2009, al-Asiri fitted out his brother, Abdullah al-Asiri, with a PETN-based underwear bomb to kill Prince Mohammed bin Nayef, a top Saudi security official. The device killed his brother instantly but failed to kill its target.
The government of Yemen has been fighting al Qaeda in the Arabian Peninsula for years with mixed results.
On Sunday, an airstrike in Yemen killed a senior operative of the al Qaeda affiliate wanted for his role in the 2000 USS Cole bombing, officials said.
Al Quso, 37, was killed while riding in a vehicle in the Rafdh district in Shabwa province. He was hit by a CIA drone strike, U.S. officials said.
In February, three months before he was taken out, al Quso was asked whether the group had stopped exporting terror operations to the outside.
"The war didn't end between us and our enemies," he replied. "Wait for what is coming."
The weekend attack plus the foiled airline plot delivered a "one-two punch" against al Qaeda in the Arabian Peninsula, a senior administration official said.
"This was a key victory for us. It also reminds us though that this war is not going to end in Afghanistan," King added. "Al Qaeda has metastasized and morphed. And they are constantly attempting to find new ways to get at us."