Bangkok (CNN) -- Anti-government protesters in Thailand have stormed the offices of the country's finance ministry, as mass demonstrations raise political tensions to the highest level since the deadly unrest of 2010.
Anti-government protest leader Suthep Thaugsuban, a former deputy prime minister under the previous Democrat-led government, led the group of protesters who entered the ministry compound, in the protesters' boldest act since demonstrations broke out three weeks ago.
Sunai Phasuk, a senior researcher with Human Rights Watch, told CNN the compound had been taken over by protesters, pockets of whom had become increasingly hostile to local and foreign media.
He said a German photographer had earlier been attacked during a protest at the headquarters of the Royal Thai Police Monday morning, where thousands of demonstrators had called for an audience with police bosses. "We demand to meet with Police Commissioner-General Adul Saengsingkaew," protest leader Puttipong Punnakun told CNN.
More than three weeks of anti-government protests led by the opposition Democrat Party rose to a crescendo Sunday as about 100,000 demonstrators turned out in Bangkok, and escalated Monday as leaders vowed to extend their rallies to government offices, TV networks and military installations.
Thaugsuban told demonstrators gathered Sunday of plans to march on media outlets and government buildings Monday, calling on civil servants to join the cause.
"We will separate into 13 groups to march to 13 locations to express our stance," he said. "Our protest will not stop until Thaksin's regime is wiped out."
Protest leaders are calling for an end to the government of Yingluck Shinawatra, sister of former premier Thaksin Shinawatra, the telecommunications tycoon who was ousted in a 2006 coup.
Critics of the Thai prime minister accuse her of being a puppet of her older brother Thaksin, a deeply polarizing figure who was removed from power by the military while in New York in 2006. He has since lived in exile, except for a brief return in 2008, and was convicted by Thai courts for corruption and sentenced in absentia to two years in jail later that year.
The current protests have reanimated the tensions along Thailand's political faultlines -- Thaksin Shinawatra's mostly rural support base on one side, the Bangkok-based elite and middle classes on the other -- that left the country wracked with turbulence for four years after the 2006 coup, culminating in a 2010 army crackdown on Thaksin supporters that left more than 90 dead.
An estimated 40,000 pro-government "red shirts" -- many from the rural areas -- gathered in a Bangkok stadium Sunday in a show of support for the embattled prime minister, who came to power in a 2011 election.
The current round of protests was triggered in response to a government-backed amnesty bill that could have extended a pardon to Thaksin Shinawatra and opened the door for his return to Thailand.
The Thai senate rejected the amnesty bill on November 11, but since then demonstrations have only grown, with Suthep calling for the current government to be replaced by a new administration.
Yingluck Shinawatra has responded to the escalating situation with a call for unity, reconciliation and respect for law. "The government has instructed police and all security officers to handle the situation gently, based on international practices, so the demonstration won't be used as a tool by people who want to make changes in a non-democratic way," she said in a statement on her official Facebook page.
More than a dozen countries have issued travel warnings for citizens to avoid areas near protests in Bangkok.