Foreign Minister Surapong Tovichakchaikul said it was alarmist of the US embassy to advise its citizens yesterday to stock up on two weeks' supply of food and water ahead of what protest leaders said would be a prolonged siege of Bangkok.
He said: "People will live their normal life. Don't be afraid of things that will happen because we try to control the situation."
Demonstrators led by former opposition politician Suthep Thaugsuban aim to paralyse the capital for between 15 and 20 days, by blocking seven main road junctions, causing gridlock in a city clogged with traffic at the best of times.
The turmoil is the latest episode in an eight-year conflict that pits Bangkok's middle class and royalist establishment against the mostly poorer, rural supporters of Ms Yingluck and her brother, former premier Thaksin Shinawatra.
The protesters want to suspend what they say is a fragile democracy destabilised by Thaksin, whom they accuse of nepotism and corruption. They want to eradicate the political influence of his family by altering electoral arrangements in ways they have not spelt out.
Thaksin was ousted by the military in 2006 and sentenced to jail in absentia for abuse of power in 2008, but he still looms large over Thai politics, the dominant force behind his sister's administration from his self-exile in Dubai.
The authorities say they will deploy more than 14,000 troops and police on Monday, including police at the main airport, to maintain order in the streets.