THE men arrested in Indonesia on the weekend planning to bomb the US embassy in Jakarta and a building across the road from the Australian embassy are likely to be tied to terror group al-Qaeda in Indonesia and were unusually sophisticated in their knowledge of explosives.

International Crisis Group expert Jim Della-Giacoma told Fairfax yesterday that the 11 men arrested by Indonesian police on Friday and Saturday had been found with the explosive nitroglycerin.

He said the men were former members of Salafi group HASMI — whose leaders have since denied any link to terrorism.

‘‘Salafis are generally known to be anti-terrorists and the transformation from Salafi to jihadi is rare, but it has been known to happen,’’ Mr Della-Giacoma said.