A military court run by the Islamist Hamas movement in Gaza extended on Monday the detention of British journalist Paul Martin for another 15 days, DPA reported.
Martin had arrived in Gaza in February to give evidence in the trial of a Palestinian militant accused of collaborating with Israel, before being arrested himself in connection with the case.
Gaza's de-facto Hamas government accuses Martin of having violated "general security" because he had interviewed the Palestinian, who had allegedly revealed secrets "to hostile bodies" by giving the interview.
Martin's detention was extended on the request of a Hamas lawyer.
"The court decided to extend Paul Martin's detention for another 15 days to finalize the attorney's investigations," said Sharhabil al-Za'eem, Martin's lawyer.
Martin had interviewed the Palestinian in January.
Al-Za'eem said the attorney had asked the court for a 30-day extension, but this was rejected and the court ruled on an extension of 15 days.
The Gaza-based lawyer was asked by the British consulate in Jerusalem to defend Martin.
The freelance reporter was accused by Hamas of being the "connection" between the militant and Israel.
"I spoke to Martin several times and he completely denied the attorney's accusations and said he is completely innocent. He told me he wouldn't come to Gaza on his own if he did anything wrong," said al-Za'eem.
"I applied to the court to let Martin have a radio, books and magazines. The judge promised that the appeal would be carefully studied," he added.
Hamas seized control of Gaza in June 2007, routing Palestinian president Mahmoud Abbas' security forces.
Israel failed to weaken Hamas' hold on Gaza during its three-week war on Gaza last winter.