Announcing her decision, US Magistrate Judge Nan Nolan told Rana, "I am sure you would be disappointed. But you have to keep doing the best you are doing."
After the hearing, Rana shook hands with his lawyer and was handcuffed before he was taken out of the court. Nolan ruled that Rana is a 'risk of flight' since he maintains strong family ties with Canada where his father and siblings live and 'has some but not substantial ties to the US.'
Pakistani-origin Canadian citizen Rana was arrested by the Federal Bureau of Investigation in October on charges that he was helping co-conspirator David Coleman Headley plot an attack on a Danish newspaper.
US prosecutors filed fresh papers on Tuesday that claim that 48-year old Rana 'knew in advance' of the 26/11 Mumbai terror strikes and 'complimented' terror outfit Lashkar-e-Tayiba on the attacks.
Rana, who runs an immigration business and grocery store in the city, has travelled extensively outside the US, going to countries like Dubai, China, India, UK, Germany and Saudi Arabia and has a lot of international contacts, Nolan added.
With a net worth of $ 1.6 million, Rana also has 'significant financial resources,' which could be used if he has to fly out of the country, the Judge said.
The judge also noted that since Rana owns and operates an immigration business, he would have 'expertise in immigration business and more means and knowledge to flee.'
"Due to all these reasons, Rana poses a serious risk of flight," Nolan said after the 45-minute-long court hearing. Talking to reporters after the hearing, Rana's lawyer Patrick Blegen said 'obviously' his client is 'disappointed' but in the 'light of the circumstances, his spirits are good.'
"But he is as am I very much looking forward to contesting these charges when we get our opportunity in court," Blegen added.
On whether David Headley's 'cooperation' in the case impacted Rana's case, Blegen said, "Headley is cooperating with the investigation. I don't know whether he is cooperating against Rana or not. I am not privy to the information yet, if Headley is cooperating he may not be telling the truth."
"The government has got an extension of time to return the indictment until January 14 and if they indict on that day, the process of fighting the case in earnest will begin," he said.
Rana's family was willing to offer a million dollar in bond to release him but the judge said this was not 'sufficient.'
The government had argued that Rana, who also possesses an expired Pakistani passport, be detained pending trial as he could be a danger to the community and is a serious 'risk of flight.'
"The government has met its burden of showing serious risk of flight," Nolan said adding the court finds that Rana could face incarceration for a long time -- up to 30 years -- which 'could give him a motive to flee.'
While there is no evidence that Rana has 'personally' any inclination to violence, 'the court is concerned about Rana's contacts with foreign terrorist organization,' Nolan said.