Two Iranians were charged in the kingdom Wednesday in connection with the third bomb incident to shake world capitals in less than 24 hours, but Tehran has rejected Israeli accusations that it is behind a terror campaign.
"Security measures have been beefed up across the country since the blasts," national police spokesman Major General Piya Uthayo told AFP.
"There's a particular focus on embassies, places where foreigners gather and tourist spots," he said.
Thai police chief Phrewphan Damapong confirmed that Israeli diplomats were the intended target of the botched plot, which came to light following an apparently unintended explosion at a house in Bangkok on Tuesday.
One of the fleeing Iranian suspects had his legs blown off as he hurled an explosive device at Thai police, officials said.
A second Iranian suspect was detained trying to leave the country while a third suspect fled to Malaysia where he was arrested, they said.
Israel accused Iran over the Bangkok plot, as well as attacks on Israeli embassy staff in India and Georgia on Monday.
An Israeli diplomat in New Delhi suffered grave shrapnel wounds when a motorbike assailant attached a bomb to her car on Monday.
Iran, which has already denied responsibility for the Delhi and Tbilisi incidents, said it had no link to the Bangkok blasts and blamed what it called "elements linked with the (Israeli) Zionist regime".
Bangkok has been on the watch for a terror attack since police last month charged a Lebanese man suspected of planning a strike, following a US warning that tourist areas might be targeted.
Authorities said Thursday they had boosted police patrols at Bangkok's Suvarnabhumi Airport, the main gateway into the kingdom, whose tourist-friendly image has been tested by a series of security scares as well as last year's devastating floods.
"We are stepping up overall surveillance and will focus on passengers behaving suspiciously as well as abandoned luggage or packages," said airport director Somchai Sawasdeepon.
Hotels have also been put on alert, particularly in major tourist destinations such as Phuket, Koh Samui and Chiang Mai.