MANAGUA (AFP) - Agence France-Presse on Saturday called for the "immediate release" of photojournalist Hector Retamal, who has been detained without charge by police in Nicaragua for four days.

Mr Retamal, a 37-year-old Chilean, was arrested Tuesday night near the presidential residence in Managua, police said. He was headed there to cover the meeting of Nicarguan President Daniel Ortega and Palestinian foreign minister Riyad al-Malki.

"We are worried about our colleague and we demand his immediate release," AFP's Central America director Marcelo Brusa said. "We don't know what he is accused of."

Since Tuesday, he has been held incommunicado in the offices of a police unit that handles cases of terrorism, drug trafficking and organised crime.

He has not had any access to a lawyer and, over the course of the four days received just two visits from Chilean consul Diego Rivera. The last was on Thursday evening.

"The detention is illegal," said lawyer Raul Arevalo, who has filed an appeal for Retamal's release. "The police have 48 hours to gather the information they need but he remains in custody and no charges have been filed." The French embassy has taken steps to secure his release.

The president of Nicaragua's foreign correspondent's association ACEN, Sonia Gonzalez, asked the presidential spokesman and first lady Rosario Murillo to help to "promptly resolve" the situation.

"Our job is to cover journalistic events in Nicaragua and that is what Mr Retamal was doing Tuesday night," she said in a letter. There has not been a response.