A legal team from The Hague has reportedly been jailed in Libya after being detained over a visit to Muammar Gaddafi's imprisoned son Saif al-Islam. The four-strong International Criminal Court (ICC) team was moved to a jail in the mountain town of Zindan, a militia brigade chief told BBC News. They were detained on Thursday and will be held for 45 days pending investigation, Ajami al-Ateri said. A second ICC delegation has arrived in Libya in a bid to free them. A member of the team being detained, Australian lawyer Melinda Taylor, has been accused of trying to pass documents to Saif al-Islam Gaddafi, who is also being held in Zintan. A spokesman for Libyan Prime Minister Abdurrahim El-Keib said the government's relations with the ICC could not be allowed to interfere with national security. The four were moved to the jail in Zintan under orders from the attorney general's office and the defence ministry, said Mr Ateri, head of the Zintan brigade. The Libyan foreign ministry confirmed the 45-day detention period but said the four were still being held in a guest-house. Meanwhile, a British Embassy convoy in the city of Benghazi came under attack on Monday afternoon. The embassy said all its staff were accounted for, and it was "liaising closely with the Libyan authorities on the matter". 'Secret code' 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". The Australian authorities say they are seeking consular access to Ms Taylor as well as clarification on the circumstances of her detention. "We are calling on the Libyan government to expedite the end of Ms Taylor's detention," Australian Prime Minister Julia Gillard told reporters. Ms Taylor's Lebanese interpreter, Helen Assaf, is being held with her, while two other ICC staff, Spaniard Esteban Peralta Losilla and Russian Alexander Khodakov, are said to have stayed with their colleagues of their own accord. The second ICC team arrived in Libya on Sunday and Libyan officials say they are holding meetings with them in Tripoli. The team hope to visit the detainees in Zintan by Tuesday. "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. Members of the Zintan brigade say the ICC team were carrying documents including a letter from a former confidante of Saif al-Islam who is now in Egypt. The letter contained drawings and symbols, a "code" that would only be understood by the sender and by Saif al-Islam himself, Ahmed al-Jehani, Libya's envoy to the ICC, told AFP news agency. The head of the Zintan brigade said protests would be held in the town calling for the delegation to be prosecuted. Stalemate Saif al-Islam, who was captured last November by militiamen as he tried to flee the country, has been indicted by the ICC for crimes against humanity. Libya's interim government has so far refused to hand him over for trial in the Netherlands - the seat of the ICC. Libya has insisted he should be tried by a Libyan court. His father was killed after being caught by rebels. The stalemate appears to be getting more complicated by the minute for The Hague, the BBC's Rana Jawad reports from Tripoli. Public opinion in Libya has been very critical of the ICC and this latest incident involving their staff, our correspondent adds.