By Prak Chan Thul
PHNOM PENH (Reuters) - Thousands of supporters of Cambodia's defiant opposition rallied on Saturday to demand an independent probe into July elections they say were rigged to prolong the rule of a prime minister now facing his biggest political challenge in two decades.
The Cambodia National Rescue Party (CNRP), the amalgamation of what was once an impotent opposition to Hun Sen's iron-fisted rule, claims it actually won the election and has vowed to hold protests until their demand was met and urged the international community to disregard the result of the national poll.
The long-dominant Cambodian People's Party (CPP) has denied foul play and Hun Sen has said he will ignore the opposition challenge and forge ahead with forming a government.
The CPP won the election with a greatly reduced majority, signaling widespread dissatisfaction with his government, despite rapid economic growth and success in reducing poverty.
"We're here today ...to seek justice for voters who demand an independent committee to investigate election irregularities," CNRP leader Sam Rainsy told a crowd of about 20,000 people at Phnom Penh's Freedom Park, the only venue where demonstrations are allowed.
"We must end violence and impunity," said Rainsy, who returned from self-imposed exile to bolster the opposition's election campaign. "The forests are gone, the farmland is gone, there's no jobs, our youth has no future. We must work together to rescue the nation."
The CNRP has urged supporters not to march in the city, fearing violence could easily erupt. Security forces have cracked down hard on strikes and protests by disgruntled factory workers and victims of a spiraling number land evictions.
Thousands of riot police armed with batons and shields have this week been running crowd control drills. Security forces manned posts on nearby streets as protesters, in yellow headbands with peace signs written on their cheeks, arrived.
Hun Sen's CPP has said it won 68 of the 123 parliamentary seats in the election, compared to the CNRP's 55 seats, a hefty loss of 22 seats for a ruling party that has formed a close but unpopular political alliance with China, its biggest investor.
But CNRP maintains it won 63 seats to the CPP's 60 and Rainsy has accused the CPP of colluding with the National Election Committee to steal 2.3 million votes from his party.
The CNRP's refusal to back down is the biggest political test in two decades for 61-year-old Hun Sen, one of the world's longest-serving leaders and a strongman who has taken credit for steering Cambodia away from its chaotic, war-scarred past towards economic growth and rural development.
But his achievements might not carry so much weight nowadays. About 70 percent of the population are under 30 and yearn for change, born long after the horrors of the Khmer Rouge's 1975-79 reign of terror and too young to remember any other government.
CNRP has recruited a powerful ally in the country's biggest labor organization, the Free Trade Union, which has fought with the government over a minimum wage the CNRP has promised to nearly double. FTU members joined representatives of farmers forced off their land in speeches denouncing the government.
It has also tapped Cambodia's tech-savvy youth, promoting itself on social media to counter the government's strict control of the airwaves and print press.
Senior CPP lawmaker Cheam Yeap said his party had no intention of bowing to CNRP's demands and accused Rainsy of being "ambitious and greedy".
"There is no truth in his allegations," Cheam Yeap said. "It's like he's claiming he won the election."
(Editing by Martin Petty and Michael Perry)