LONDON [MENL] -- Syrian special operations forces were said to have surrounded the office of the nation's military intelligence chief, regarded as the leading suspect in the assassination of former Lebanese Prime Minister Rafik Hariri.

The opposition Arab News Network satellite channel, owned by the uncle of Syrian President Bashar Assad, reported on Wednesday that elite Syrian troops have laid siege to the office of military intelligence chief Gen. Assaf Shawkat. The London-based ANN said the siege was meant to pressure Shawkat to surrender to Syrian authorities and undergo interrogation by United Nations investigators.

The ANN report was not confirmed by any other source. ANN, led by Assad's uncle and deposed vice president Rifat, has been regarded as a leading media outlet for the Syrian opposition.

The report capped a period of rising tension within the Syrian regime in 2005. Last week, Syrian opposition sources said the Assad regime was arming Alawi militias to prepare for the prospect of a civil war with the majority Sunni community.