The US embassy on Monday rejected a call from Prime Minister Yingluck Shinawatra to lift its terrorist threat warning for Bangkok.
US embassy spokesman Walter Braunohler told the Bangkok Post on Monday afternoon that the emergency message to American citizens will remain despite the arrest of a suspect believed connected to terrorism and an appeal by Ms Yingluck that the warning would damage Thailand's image.
Mr Braunohler said it was safe to say there was heightened awareness and specific heavier measures in place since the alert was issued and therefore it would be maintained as long as there was the possibility of terrorist attacks in the capital in the near future.
Asked what it would take for the advisory to be lifted, he declined to respond.
As to the adverse impact on tourism and heightened fears among foreign embassies, Mr Braunohler said: "The safety of American citizens is a priority and the embassy has to ensure the US people have the same information that the embassy gets when it comes to specific, credible information".
The Israel embassy said it did not have any statement to make on the issue.