Five Pakistanis and an Afghan have been held for illegally entering the United States (US) confirmed the US Federal Bureau of Investigation (FBI).

Though, the six has not been suspected as terrorists but were earlier detained in Arizona in December.

They were arrested for ten days after the Dec 2 terrorist attack in San Bernardino, California, where a Pakistani-American couple had killed 14 people reports Dawn.

An FBI official told reporters that the accused were checked through the national security databases by Joint Terrorism Task Force but their possible links to terrorism has not been proved.

An FBI spokesman told an NBC affiliate in Arizona that all six men were then placed in the custody of the US Immigration and Customs Enforcement.

A US Customs and Border Protection official told the NBC affiliate that Pakistani and Afghan national's make up about 0.1 per cent of border crossers at all US borders.