BANGKOK (AP) — Tourists in the Thai capital should brace for more traffic than usual and avoid sites near anti-government protests this weekend that authorities fear could turn violent, the government spokesman said Wednesday.

More than 30,000 security officials will be deployed around Bangkok and 46,000 "civilian defense volunteers" are on standby for rallies scheduled to start Friday and run several days, said the government spokesman, Panitan Wattanayagorn.

Supporters of ex-leader Thaksin Shinawatra, who was deposed in a 2006 coup, have called for a "million man march" to begin nationwide Friday and converge in the capital Sunday, where they plan to possibly remain several days.

Authorities estimate the turnout will be tens of thousands. On Tuesday, the government invoked its Internal Security Act, a law that gives the military special powers to restore order if necessary. It cited intelligence reports about plans to instigate violence at the rallies.

"We have confidence that we can manage to get through this situation peacefully," Panitan told a news conference attended by police, military and Bangkok city officials. "But due to the large number of demonstrators planning to come we have concerns."

Tourists and foreigners are not targets of the protesters, who are calling for Prime Minister Abhisit Vejjajiva to resign and pave the way for fresh elections.

Popular tourist attractions the Grand Palace and backpacker street Khao San Road are "areas of concern" because of their proximity to the main protest site, said Bangkok Metropolitan Authority spokesman Thanom Onkeppol. Protesters plan to gather at an open field near the Grand Palace, and spread around the area.

Tourists should avoid the areas "if that's possible," said Panitan, adding that more than 50,000 tourists pass through the Thai capital every day.

Some two dozen foreign embassies have issued advisories, including the United States which urged Americans to stay away from the protests where "violence cannot be ruled out."

Protest leaders from the pro-Thaksin movement, the United Front for Democracy against Dictatoriship have repeatedly said they will gather peacefully and accuse the government of hyping security concerns to make them look bad.

Authorities fear a repeat of April 2009 when tens of thousands of Thaksin supporters paralyzed major Bangkok intersections and sparked violence that killed two and injured more than 120 people.

Thailand has been gripped by a political crisis and sometimes violent protests since 2006, when Thaksin was ousted for alleged corruption and abuse of power. In 2008, when a pro-Thaksin administration was in power, anti-Thaksin activists seized Bangkok's two airports and stranded thousands of tourists.

Bangkok's international Suvarnabhumi Airport has a contingency plan in case of emergency, an airport statement said Wednesday. International passengers were advised to get to the airport three to four hours before their flights depart.