(Updates with details of detentions, siege)
By Yves Herman and Philip Blenkinsop
BRUSSELS, Nov 16 (Reuters) - Two people detained in Belgium on Saturday are being held on terrorism charges for their suspected role in the attacks on Paris, Belgian federal prosecutors said on Monday.
The two, about whom officials gave no details, face charges of leading a terrorist attack and taking part in the activities of a terrorist organisation.
Five other people also detained on Saturday were released after going before a judge.
The prosecutors also said that the search of a house in the Brussels district of Molenbeek, which was under police siege for four hours, failed to produce evidence and no arrests were made.
The local mayor and media had earlier said at least one person had been detained.
Police said that operation was related to the Paris attacks and the search for Salah Abdeslam, a 26-year-old Frenchman living in the Belgian capital for whom an international arrest warrant has been issued.
A Reuters journalist at the scene said that three special force commandos wearing gas masks entered the besieged house via the roof. After about 10 minutes, they came out of the front door. Armoured vehicles were also in position.
Abdeslam had rented a Belgian-registered car found in Paris and suspected of having been used by the attackers, one of whom was Abdeslam's brother Ibrahim.
He was pulled over with two other people in another car, a Volkswagen Golf, in northern France, near the Belgian border, just after 9 a.m. (0800 GMT) on Saturday morning, but then released. The car was later found in Molenbeek on Saturday afternoon.
The poor district of Molenbeek, home to many Muslim immigrants, has been at the centre of investigations of militant attacks in Paris over the weekend, after it emerged that two of the attackers had lived in the area.
French President Francois Hollande said on Monday that Friday's attacks were planned in Syria and organised in Belgium.
A source close to the French investigation told Reuters that Abdelhamid Abaaoud, a Belgian national currently in Syria, was investigators' best lead as the person likely behind the killing of at least 129 people. However, Belgian prosecutors said this was an unconfirmed rumour. (Additional reporting by Robert-Jan Bartunek; Editing by Giles Elgood)