The Cambodian opposition's largest-ever marching against Prime Minister Hun Sen's government on Sunday ended peacefully after at least 20,000 protesters had spent about four hours walking through streets in capital Phnom Penh. The protests, led by Sam Rainsy, president of the Cambodia National Rescue Party (CNRP), entered the eighth day on Sunday and seemed the biggest-ever marching in the capital since July's disputed election that handed victory to Premier Hun Sen's ruling party. Protesters brandished flags and shouted in chorus "Hun Sen must step down." The demonstrations were to demand Hun Sen hold a re-vote or to step down following allegations of serious irregularities during July's election, said Sam Rainsy. "Political tsunami has begun in Cambodia and it will be the biggest of all on Sunday next week," Sam Rainsy announced to his supporters at the Freedom Park after the march, adding that daily protests are still going on. Most of the protesters had been trucked from provinces in the morning to join the protests and transported back to their homes in the evening. National Military Police spokesman Kheng Tito said general situation in the city was good on Sunday since protesters had marched peacefully. "There is not any report of clashes," he told Xinhua on Sunday night. "Since protesters had walked peacefully, our forces had helped facilitate traffic for them." Prime Minister Hun Sen on Friday refused to step down or to call a re-vote, saying that he has done nothing wrong. "I have ascended to the prime minister through the constitution. If I descend, it will also be through the constitution," he said. "Therefore, I confirm that there is no re-election because no one can dissolve the National Assembly and no mechanism states about a snap election before the end of the term." According to Article 78 of the country's constitution, the National Assembly shall not be dissolved before the end of its five-year term, except when the royal government is twice deposed within a period of 12 months. "So, in Cambodia, the Prime Minister, the King, and the National Assembly itself have no rights to dissolve the parliament, " he said. The premier also warned to take legal action against protesters if they blocked highways or seized government buildings. Political row between Hun Sen's ruling party and Sam Rainsy's opposition party has persisted since the July election results showed that the ruling party won a majority of vote with 68 parliamentary seats against 55 seats for the opposition. The opposition refused to accept the outcome and has boycotted parliament since then. Despite the opposition's boycott, the ruling party-formed parliament voted on Sept. 24 for the establishment of a new government under the leadership of Prime Minister Hun Sen. Sam Rainsy reiterated on Sunday that the party would continue boycotting parliament unless there is an appropriate solution to July's contested election.