"Probably thousands upon thousands upon thousands of names were scrubbed, and probably dozens were moved to different lists," he added of the reviews carried out in the wake of a botched Christmas Day bombing of a Northwest jet.
New rules at international airports also went into effect from early Monday, meaning all passengers boarding US-bound flights may now be subjected to random checks and baggage searches.
Further boosting security measures, all travelers coming from or via 14 "terror linked" countries will have to undergo compulsory enhanced screening.
Afghanistan, Cuba, Iran, Libya, Nigeria, Pakistan, Somalia, Sudan and Syria are among some of the other countries affected.
The alleged bomber of Northwest Flight 253, 23-year-old Nigerian, Umar Farouk Abdulmutallab, boarded the plane in Amsterdam, after arriving from Lagos.
Nigerian officials have said, however, he started his journey in Ghana, and they hit out at the new rules, saying it amounted to discrimination.
"It is unfair to discriminate against over 150 million people because of the behavior of one person," Information Minister Dora Akunyili told journalists.
The new security measures have caused confusion in some airports, including at Rome's Fiumicino where passengers headed to the United States faced major delays at security checks.
The Dutch airport Schiphol, where Abdulmutallab boarded the plane for Detroit, is also to get 60 new full body scanners to cover all US-bound flights in addition to 15 already installed.
The scanners will be operational at Schiphol "in the coming months," spokeswoman for the Schiphol Group, Mirjam Snoerwang, told AFP.
Britain, meanwhile, denied accusations that it failed to share information about Abdulmutallab, a graduate of University College London who was put on a watchlist barring him from future entry into Britain in May 2009.
Prime Minister Gordon Brown's office said information gathered while he was a student in London between 2005 and 2008 had been passed to US authorities.
"Clearly there was security information about this individual's activities and that was information that was shared with the US authorities. That is the key point," Brown's official spokesman told reporters.
As the investigation into the botched bombing continued, US President Barack Obama held more talks ahead of a key meeting Tuesday with intelligence and security chiefs at the White House.
FBI agents were also in Ghana investigating Abdulmutallab's stay where he allegedly bought the ticket for the bomb targeted flight.
"The investigation will allow the FBI agents to gather more information on the suspect's stay in Ghana," Deputy Information Minister James Agyenin-Boateng told AFP.
Abudmutallab is also said to have spent time in Yemen where he came into contact with a cell of the Al-Qaeda network.
Al-Qaeda in the Arabian Peninsula (AQAP) has said it was behind the Christmas Day plot to blow up the plane over Detroit which failed when chemicals sewn into Abdulmutallab's underwear failed to explode correctly.
With Western pressure growing for Sanaa to tackle AQAP, Yemeni forces shot dead two Al-Qaeda militants Monday in a bid to capture Mohammed al-Hanq, one of the group's most senior leaders, who managed to flee the firefight.
France also became the latest country to close its embassy in Sanaa, following a move by Britain and the United States on Sunday.
Paris said it would "no longer authorize public access to the premises of our diplomatic mission" while Japan and the Netherlands halted consular services and Italy said it would only deal with people with appointments.
US Secretary of State Hillary Clinton said the US embassy would remain closed until the security conditions were deemed to have improved.
Yemeni Foreign Minister Abu Bakr al-Kurbi, however, Monday rejected any comparison between his country and Afghanistan as an Al-Qaeda haven.
"The situation is different in Yemen and cannot be compared to Afghanistan," Kurbi told reporters during a visit to Doha.
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