Thousands of people in Thailand have started a massive clean-up campaign in Bangkok's charred commercial district following weeks of protests and violence.

Volunteers scraped away political graffiti and posters Sunday and carted away garbage left by protesters.

Bangkok's two main mass transit systems, the Skytrain and the subway, reopened Sunday after a week's closure. Government offices, schools, and the stock exchanges are expected to reopen Monday.

However, Prime Minister Abhisit Vejjajiva said on Sunday a curfew in Bangkok and 23 provinces will be extended for more two nights. The curfew was imposed Wednesday, after Bangkok suffered the worst riots in the country's modern history.

At least 83 people have been killed and another 1,800 wounded since anti-government Red Shirts began their demonstrations in March.

The prime minister called Friday for national reconciliation, promising the government will meet the "huge challenges" ahead as it seeks to heal deep political divisions.

Red Shirts and human rights groups have condemned the government's use of deadly force to break up the protests.

Mr. Abhisit said Sunday he is willing to hold early elections before his term expires, but said he will only do so where there is peace. During the standoff with protesters, Mr. Abhisit offered to dissolve parliament and hold new elections on November 14 - key demands of the Red Shirts.

Some information for this report was provided by AFP and Reuters.