Bogota  - Colombian President Alvaro Uribe backtracked Monday and authorized opposition Senator Piedad Cordoba to be part of a mission that is set to go in search of two further hostages that leftist rebels plan to release.

In a highly controversial decision, Uribe had originally decided to prevent the group Colombians For Peace - made up of journalists, politicians and academics and led by Cordoba - from taking part in any releases after comments made by members accused the Colombian Armed Forces of coming close to frustrating other releases Sunday.

The Revolutionary Armed Forces of Colombia (FARC) freed Sunday four hostages who had been held since 2007. They were handed over at an undisclosed site in jungles in southern Colombia.

FARC has said it intends to release another hostage on Monday, the former governor of Meta province, Alan Jara, and another on Wednesday, former Colombian parliament member Sigifredo Lopez.

The arrival of three police officers and one soldier from the jungle in southern Colombia to the city of Villavicencio was said to have taken a lot longer than planned due to the presence of unidentified aircraft in the area where they were released by the rebels, even though the government had granted the mission full security guarantees.

A spokesman for Colombians For Peace, journalist Jorge Enrique Botero, accused the Armed Forces of having been in the area.

The government initially denied the allegations. However, Uribe later admitted that there were indeed Air Force planes in the area, but not in a position to affect the operation. He was so angry about the allegations that he banned Colombians For Peace from taking part in any further releases.

In a brief statement, Uribe responded to a request from the International Committee of the Red Cross for Cordoba to be allowed to take part in the releases "out of solidarity with the kidnapped and their families." Several observers had said the rebels would not release their hostages if the senator was not there.

However, the president expressed a "worry over the exaltation of terrorism that took part" Sunday, with reference to the allegations of Colombians For Peace. dpa