The U.S. State Department has issued a travel alert for Thailand, warning visitors about demonstrations sparked, in part, by elections next month.
"The situation is unpredictable and ongoing demonstration activity, primarily in the greater Bangkok area and occasionally elsewhere in Thailand, is expected to continue," the alert on the State Department's website says.
"U.S. citizens are advised to avoid all protests, demonstrations and large gatherings. Some protest sites are ... near tourist attractions and popular shopping malls, which at times have closed or shortened hours unexpectedly."
Thailand on Tuesday declared a state of emergency.
The demonstrations have become increasingly violent in recent days. On Friday and again on Sunday, explosives were detonated, and at least one person was killed and more than three dozen were injured.
Demonstrators are seeking to get rid of Prime Minister Yingluck Shinawatra, who called an election for Feb. 2.
Legislation that would have allowed the prime minister's brother, Thaksin Shinawatra, himself a former prime minister, to return to politics has sparked outrage. Thaksin Shinawatra was ousted in 2006 amid charges of corruption and abuse of power. His exile is self-imposed.
Travelers probably will encounter some disruptions.
"The Thai government has invoked its Internal Security Act (ISA) throughout Bangkok, which allows authorities to close roads, make arrests; take action against security threats; and increase police presence around government buildings and at other locations," the State Department's alert said. "Police have used tear gas, rubber bullets and other measures to protect government facilities at several locations."
The State Department alert expires Feb. 14.