Sri Lankan authorities locked down the central bank and the road leading to Colombo's jittery airport was shut briefly by a bomb scare yesterday, as more people were swept up in the search for those behind Easter Sunday bombings that killed 359.
Two bank officials said the street outside the building near the World Trade Center in the capital was blocked to traffic before the security alert was lifted.
Underscoring the nervous atmosphere in the country, authorities also shut the entry road to the main airport after a suspicious vehicle was identified at a nearby carpark. The road was reopened when the alert was declared a false alarm.
A police spokesman said there was an unexplained explosion in a town east of the capital although there were no casualties.
With fears of more bombers ready to strike, police said they had asked people to leave offices early in Colombo's business district to avoid throngs at rush hour. City-center restaurants were also shutting early.
More people, including foreigners, were swept up for questioning overnight as domestic and international authorities probed deeper into the bombings. About 500 people were also wounded in the attacks on three churches and four hotels.
Police said an Egyptian and several Pakistanis were among those detained overnight, although there was no immediate suggestion they had direct links to the attacks.
A picture has slowly emerged of a group of nine well-educated, homegrown Islamist suicide bombers, including a woman, who carried out the attacks.
The bombings shattered the existing relative calm in Buddhist-majority Sri Lanka since a civil war against mostly Hindu, ethnic Tamil separatists ended 10 years ago.
Hundreds of Pakistani Muslims have fled Colombo, crammed into buses, fearing revenge.