South African coach Mickey Arthur Monday said he was still apprehensive despite assurances from Sri Lanka's cricket authorities that the tri-series would go ahead with tighter security for the teams.
"They tried to explain how a cricket event or the teams were least likely to be targeted," Arthur told reporters at the team hotel.
"But this was quite close to home and we're pretty worried. It's fair to say that if we hadn't been playing today (yesterday), a lot of our boys might have been over at Liberty Plaza (the shopping arcade near the blast site).
"The mood within the team is tense. The situation seems to be getting worse too, if you watch the news and read the papers. We saw that a truck full of explosives had been stopped just outside of Colombo.
"The final decision though will be made by our security men in consultation with the cricket boards. They're probably the best people to make a judgement."
Sri Lanka Cricket chief executive Duleep Mendis earlier told AFP after a meeting with the respective team officials that the series will go on.
"We will continue to monitor developments but the matches will be played as scheduled," Mendis said. "The security for the teams has been increased."
The blast on Monday afternoon in the same area where the teams' hotels are located targeted Pakistan's ambassador Bashir Wali Mohamed.
The ambassador was driving through the area when the blast occurred, police said, adding that a Sri Lankan military vehicle escorting him was hit by the explosion.
Four commandos guarding the diplomat were killed instantly and the other three victims were bystanders. Eight others were wounded and taken to hospital.
It was the first time in 21 years that a foreigner had been targeted in an attack in Sri Lanka's three-decades-old separatist campaign.
The attack came four days after a powerful car bomb attack on a government Tamil politician in Colombo. The politician escaped but his bodyguard and two bystanders were killed.
Sri Lankan cricket officials went into a huddle soon after the opening match between South Africa and Sri Lanka was washed out due to heavy rain.
The match is scheduled to be played on Tuesday, weather permitting, as a reserve day has been kept aside for all seven matches of the series that runs till August 29.
Indian team official Rajan Nair said the entire team was safe and confined to the cricketers' heavily-guarded hotel.
"There is nothing to worry," Nair told AFP. "The boys were in their rooms when the blast took place and did not even know that something had happened.
"We were due to leave for a practice session but it was cancelled because of the rain."
New Zealand abandoned their cricket tour of Sri Lanka in 1987 after a blast in Colombo's Pettah region, which houses the main bus and train stations, killed 110 civilians and two policemen.
The New Zealanders suffered another shock in 1992 when a blast outside their team hotel in Colombo killed the country's Naval chief Clancy Fernando. They, however, went ahead and played two Test matches and three One-dayers.