Thai PM returns to office, as protesters rally at police HQ before king's birthday

Anti-government protesters sweep streets in front of the Democracy Monument in Bangkok, Thailand, Wednesday, Dec. 4, 2013. Protesters intent on toppling Thailand's democratically elected prime minister plan to press their struggle again Wednesday with a peaceful march on Bangkok's national police headquarters, one day after a sudden truce in honor of the king's birthday this week ended a spate of increasingly fierce street fighting. (AP Photo/Vincent Thian) (The Associated Press)

A woman walks near a portrait of Thai King Bhumibol Adulyadej and Queen Sirikit on display, in Bangkok, Thailand, Wednesday, Dec. 4, 2013. Protesters intent on toppling Thailand's democratically elected prime minister plan to press their struggle again Wednesday with a peaceful march on Bangkok's national police headquarters, one day after a sudden truce in honor of the king's birthday this week ended a spate of increasingly fierce street fighting. (AP Photo/Vincent Thian) (The Associated Press)

Anti-government protesters pack their belongings after they spent a week near the Democracy Monument in Bangkok, Thailand, Wednesday, Dec. 4, 2013. Protesters intent on toppling Thailand's democratically elected prime minister plan to press their struggle again Wednesday with a peaceful march on Bangkok's national police headquarters, one day after a sudden truce in honor of the king's birthday this week ended a spate of increasingly fierce street fighting. (AP Photo/Vincent Thian) (The Associated Press)

Prime Minister Yingluck Shinawatra has returned to her office after five days away, but her effort to show that normalcy was returning to Thailand was upstaged by another rowdy anti-government rally at the national police headquarters.

After initially pledging to stage a peaceful march Wednesday, protesters knocked over concrete barriers and forced their way into the police compound. The commotion ended quickly, with police opening the gates to let protesters enter.

Authorities used the same strategy a day earlier at sites where violent clashes had erupted over the past several days between police and anti-government protesters trying to topple Yingluck's government.

The government's move was timed to coincide with national celebrations for the revered king's 86th birthday on Thursday.