All the signs are that the Obama administration is cranking up its secret war against al-Qaida in Yemen.

The acknowledgement of increasing intelligence cooperation with the beleaguered Sanaa regime, which resulted in a string of attacks on the jihadists' bases in which some 50-60 operatives were reported killed or captured over the last two weeks, is a strong indication that the Americans are showing a new determination to eliminate the militants who call themselves al-Qaida in the Arabian Peninsula.

A report carried by The New York Times Monday that the United States has opened a "largely covert front" against al-Qaida in Yemen underlines how Washington perceives the organization to be a serious threat not only to the Sanaa government, battered by a plethora of crises, but to the West, and the United States in particular.

The bizarre -- and still largely unexplained -- attempt by a Nigerian engineering student, son of his country's leading banker, to blow up a Detroit-bound Northwest Airlines flight from Amsterdam on Christmas Day has added to U.S. unease about al-Qaeda's swelling resurgence in Yemen, ancestral homeland of Osama bin Laden.

According to reports, the Nigerian, Umar Farouk Abdulmutallab, has admitted that he was trained in Yemen at an al-Qaida camp and dispatched on his suicide mission from there.

But these allegations mostly appear to originate with IntelCenter, a private contractor that Antiwar.com describes as having a "dubious reputation" and "does business with the intelligence community."

Admittedly, it's still early days in the U.S. investigation, but the plot appears to get curioser and curioser.

One passenger aboard Northwest Flight 253 described how Abdulmutallab was escorted to the check-in desk at Amsterdam's Schiphol Airport by a well-dressed "Indian man" about 50 years old who told the airline attendants that the younger man did not have a passport but had to get on the flight.

The two men were told to go see the airline manager. "I never saw the Indian man again as he wasn't on the flight," said the passenger, Kurt Haskell.

"It was also weird that the terrorist never said a word in this exchange. Anyway, somehow, the terrorist still made it onto the plane. I'm not sure whether it was a bribe or just sympathy from the security manager."

The same witness said that after the airliner landed safely in Detroit that the Federal Bureau of Investigation "arrested a different Indian man while we were held in customs after a bomb-sniffing dog detected a bomb in his carry-on bag and he was searched …

"I'm not sure why this hasn't made it into a new story, but I stood about 15-20 feet away from the other Indian man when he was cuffed and arrested."

These observations, so far not disclosed let alone explained by U.S. authorities, have prompted suspicions that the whole episode was being used to demonstrate that al-Qaida in the Arabian Peninsula poses a direct threat to the United States, not just to the corrupt regime in Sanaa, and therefore required direct action by President Barack Obama even as he cranks up the wars in Afghanistan and Pakistan.

U.S. authorities say that the bomb Abdulmutallab failed to detonate was made of a powerful military explosive, pentaerythritol, or PETN.

This was the same explosive used by al-Qaida in an abortive attempt in August to assassinate Prince Mohammed bin Nayef, Saudi Arabia's deputy interior minister and head of its counter-terrorism branch, which crushed the jihadists in the kingdom in 2007.

Most of the al-Qaida activists who survived fled to Yemen to form the core of a resurgent organization that apparently planned to renew operations against the Saudi monarchy.

Further bolstering the signals that the White House is poised to take the war to the jihadists in Yemen far more forcefully than hitherto was a September visit to Sanaa by John Brennan, Obama's counter-terrorism chief.

At the same time, Obama, in an unusually strong statement, declared the security of Yemen, which straddles the vital oil tanker routes of the Gulf of Aden and the Red Sea, to be "vital for the security of the United States."

Any U.S. escalation there will likely involve similar action in the failed state of Somalia, across the Gulf of Aden from Yemen. There jihadists linked to al-Qaida are fighting a fragile U.S.-backed transitional government. Several key figures have been assassinated by U.S. teams.