Since a wave of bombs on New Year's Eve in downtown Bangkok killed three and injured dozens, including foreign tourists, police have beefed up security at department stores, train stations and Bangkok's new international airport.

The Thai capital was again on fresh alert after Australia, Canada, Britain and Japan warned of possible terror attacks in Bangkok and urged their citizens to stay away from crowded places such as shopping malls and stations.

The foreign warnings came after Thai Defence Minister Boonrawd Somtas said Thursday Islamic separatists from the country's restive Muslim-majority south could slip into the capital and mount attacks here.

But Thai officials said Saturday no new security alert was issued, while the US Embassy in Bangkok left its travel advice on the website unchanged, urging travellers to monitor events and to avoid large public gatherings.

Kamol said police have increased security at more than 1,000 locations including embassies, government buildings, shopping malls, train stations and popular tourist hangouts since the deadly New Year's Eve bombs.

Thailand has also been hit by an insurgency in the Muslim-majority south bordering Malaysia. Nearly 2,000 people have been killed in the unrest since 2004, but the violence has largely been contained in the region.

The government earlier denied any link between the Bangkok blasts and the southern unrest, insisting the New Year's Eve bombings were the work of factions in the military or police linked to ex-premier Thaksin Shinawatra, who was ousted in a September coup.

But Thai investigators said earlier this month that a suspect in the deadly Bangkok bombings might have links to the southern insurgency.

Agence France-Presse