BANGKOK — In one of the more provocative moves of Thailand’s monthlong political crisis, antigovernment protesters marching through Bangkok on Sunday vowed to disrupt the coming elections in their campaign to rid the country of its most influential political family.

As tens of thousands of protesters rallied at several points in Bangkok, the capital, the main protest leader, Suthep Thaugsuban, instructed his followers to gather outside the building where the governing party of Prime Minister Yingluck Shinawatra and other smaller parties had planned to register for the Feb. 2 national elections.

“If you want to register, you will have to walk past our feet,” said Mr. Suthep, who vowed to organize more protests if necessary.

“We will shut down the country; we will block everyone casting ballots,” he said.

The dueling realities of Thailand’s grinding political turmoil were vividly on display on Sunday. As protesters massed in Bangkok and blocked major intersections, Ms. Yingluck was hundreds of miles away in friendly territory among adoring crowds in northeastern Thailand, the power base of her party, a vast region with a population that rivals Bangkok’s.