In front of tens of thousands of supporters in Bangkok, a Thai protest leader promised to keep the city shut down for as long as necessary.

(SOUNDBITE) (Thai) PROTEST LEADER, SUTHEP THAUGSUBAN, SAYING:

"This 'Shutdown Bangkok' will go on until we know whether we have won or lost. There is no time limit."

With whistles, clappers and flags, protesters are occupying parts of central Bangkok.

It's part of a festive citywide drive called "Shutdown Bangkok, Restart Thailand."

It's designed to pressure the government into widespread reforms.

The chief demand is the resignation of Prime Minister Yingluck Shinawatra.

Shinawatra invited opposition leaders for a meeting Wednesday to discuss an election commission, but protesters have rejected that invitation.

(SOUNDBITE) (Thai) ANTI-GOVERNMENT PROTESTER, PORNSAK SATSAWATECHA, SAYING:

"What they were trying to do is buy time, we cannot trust them. The only way that they can be trusted is when t