The detentions underscore long-standing allegations that elements in Pakistan support a militant group known as Lashkar-e-Taiba, which is devoted to fighting the country's arch enemy, India.
The group is blamed for last year's terror attacks in Mumbai and other strikes in India in recent years.
Last month's arrests of David Coleman Headley and Tahawwur Hussain Rana in Chicago have cast a fresh spotlight on the group.
U.S. prosecutors said the two men were believed to be working with an unidentified senior member of the outfit and a senior al Qaeda operative.
Two Pakistani intelligence officials, speaking anonymously because they are not allowed to release their identity, said phone records showed the five Pakistani officers had contacted Headley and Rana.
They say the five include a retired brigadier general and two active lieutenant colonels, but did not provide more details.
Pakistani military officials could not immediately be reached for confirmation.
The FBI says Headley traveled to Pakistan this year and may have been headed there when he was arrested Oct. 3 at Chicago's O'Hare International Airport en route to Philadelphia.
Indian officials say Headley also may have been involved in, which occurred a year ago Thursday.
Headley, 49, and Rana, 48, are accused of plotting to kill one of the editors and a cartoonist at Danish paper Jyllands-Posten for publishing 12 cartoons in 2005 depicting the Prophet Muhammad, whichin much of the Muslim world.
The FBI has said only that it has evidence Headley and Rana were in contact with the Pakistani group Lashkar-e-Taiba, which the Indian government blames for the Mumbai attacks that left 166 dead and 308 wounded. U.S. authorities say Headley was in contact with the group while he allegedly carried out reconnaissance this year near the newspaper offices in Copenhagen. They say Rana last year advised a member of the group on how to slip people into the U.S.
Headley is a U.S. citizen who changed his name from Daood Gilani in 2006 to get across international boundaries without too many questions at customs, according to an FBI affidavit.
He and Rana, a Pakistani immigrant to Canada who has lived in Chicago for a decade, are charged in criminal complaints with conspiring to provide material support to terrorism and providing material support to terrorism. They will not enter pleas until they are indicted.
Lashkar-e-Taiba, which means Army of the Pure, was established in the early 1990s to reclaim territories it views as Muslim land, primarily the Indian-controlled section of the disputed Himalayan territory of Kashmir. Analysts say it was largely a creation of Pakistani security agencies.