By NNN-Xinhua,
Colombo : The police in Sri Lanka said 33 people have been held on suspicion over the bomb blast which killed nine people and injured 86 more on Monday.
The blast on board a crowded train along the western coastal line hit the Colombo suburb of Dehiwala late Monday afternoon.
Officials said on Tuesday that 72 of the 86 injured are still being treated in two hospitals.
A senior police officer said 15 people out of the 33 arrested on suspicion were released after questioning.
The authorities have alerted the commuters in public transport to be aware of attempts by the Liberation Tigers of Tamil Eelam (LTTE) to explode bombs.
The government says LTTE rebels are desperate in view of the defeat they are facing in the hands of government troops in the north and east.
Bus and train bombs have become frequent since the government walked out of the six-year-old Norwegian backed ceasefire in mid-January.