''We are in close contact with them and working with them on a number of issues surrounding this,'' the White House Press Secretary Robert Gibbs said on Tuesday.
''We are in the middle of an active and ongoing investigation. Part of that active and ongoing investigation is to examine the time that this individual spent in Pakistan,'' Gibbs said at his daily news briefing in response to a question.
The FBI in its compliant told a New York court that Shahzad conceded to investigators during interrogation that he recently spent five months in Pakistan.
Pakistan-born-US national Shahzad was charged yesterday with attempted use of a weapon of mass destruction, acts of terrorism transcending national boundaries and other federal crimes for allegedly driving a car bomb into Times Square on the evening of May 1.
Shahzad was taken into custody at the John F Kennedy International Airport on May 3 when he was about flee from the country.
Gibbs said it is too early to say if he was acting alone or he was part of an international terrorist network.
"It is an ongoing investigation, and I don't have anything further on it," he said.
The incident, Gibbs said is a reminder of those that seek to harm this country and its innocent citizen.
"There is tremendous relief that nobody was hurt, and great thanks for those that in a short period of time have done the job they needed to do, to track this individual down," he said.
Gibbs said that there were people who want to harm the US, as they are opposed to President Barack Obama's nod for increasing military presence in Afghanistan to prevent Taliban and its allies from regaining power and protect the war-torn nation from again becoming a safe haven for al-Qaeda.
"So, whether it's increased tempo, whether it's Afghanistan, I don't know the answer to it exactly. I'm sure there are some that have cited both of those decisions for their misguided and murderous rages," he observed.
