The head of the Zintan brigade militia has told the BBC, that four officials from the International Criminal Court have been jailed in the town of Zintan.
Ajami al-Ateri told the BBC that the team will be held for 45 days pending investigations.
The team was detained after visiting Col Gaddafi’s son Saif al-Islam Gaddafi, who is being held by the Zintan brigade.
They are accused of trying to hand Gaddafi documents while visiting him in a prison in the town.
Nasser al-Manaa, the prime minister's spokesman, said: "The relationship between Libya and the ICC cannot be at the expense of Libya's higher interests or the allowance of security breaches or threats to national security."
He said the Libyan government expected the ICC to "co-operate in a neutral investigation".
Another ICC team was dispatched to secure the release of the officials.
"I call on the Libyan authorities to immediately take all necessary measures to ensure their safety and security and to liberate them," ICC President Song Sang-hyun said.
Saif al-Islam was indicted by the ICC for crimes against humanity, but Libya is refusing to hand him over, saying he should be tried by a Libyan court.
ICC demands release of staff in Libya (10 Jun 2012)