Sri Lankan police have intensified security alert in the capital Colombo for possible strikes by Tamil Tiger rebels, defense officials said Thursday.
Over 20 people were arrested on suspicion in Colombo in a security operation launched on Wednesday night and carried on till dawn on Thursday.
The Colombo suburbs of Mount Lavinia and Wellawatta were covered in the operation.
"We arrested 14 people each from Mount Lavinia and Wellawatta," a police official said on condition on anonymity.
Officials said the police were looking for possible members of the Liberation Tigers of Tamil Eelam (LTTE) or their accomplices in the capital after two strikes by LTTE rebels in the city during last week.
Last Thursday, the rebels targeted a military bus in downtown Colombo while on Monday they targeted another truck transporting troops in the suburb of Ratmalana.
Some nine people were killed in the two attacks with over 40 people being injured. Most of the dead in Monday's blast were civilians.
The government said that the rebels have got desperate due to their military losses in Eastern Province and are likely to carry out more attacks in the city in order to trigger a backlash on the minority Tamil community from the majority Sinhalese.
President Mahinda Rajapakse told the cabinet meeting on Wednesday that the Civil Defense Force (CDF) needs to be activated in order to tackle the growing threat of the rebels.
Under CDF, special military training is given to the paramilitary home guard brigade to assist government troops in handling security issue, officials said.