BANGKOK -- Thailand's Constitutional Court on Friday ordered the disbandment of the Future Forward Party, the country's second-largest opposition group, ruling that it illegally accepted funds from its founder.

Sixteen executive members, of which 11 are parliamentarians, will be banned from running for office or being involved in a new party for 10 years.

The party announced that it will accept the verdict.

Opponents of Thailand's pro-military government see the decision as a blow to their efforts to restore the country to full democracy. Critics have sounded the alarm over a clampdown on the opposition by the pro-military government.

Political parties in Thailand are legally barred from accepting cash donations, properties or any other benefits of more than 10 million baht ($320,000) from any one individual. The party's 41 year-old leader, Thanathorn Juangroongruangkit, pumped 191 million baht into Future Forward to fund its general election campaign last March. A petition filed by the Election Commission of Thailand called the funding a donation. Thanathorn insisted it was a loan. The court judged that it was an illegal "benefit," as the loan had a very low interest rate.

"Our one year, four months and 18 days was a beautiful journey," Thanathorn told reporters after his party, founded in 2018, was ordered to be dissolved. "As the leader of the party, I would like to apologize to people that we could not deliver our promises.

"This is a time to stand firm. This is not a time to be sad or cry. We have no time for that. Our vehicle, called a political party, has been halted, but people will continue on the journey."

Thanathorn cajoled party members and supporters to march ahead under the renamed Future Forward Movement.

"As a Thai citizen I would like to use my right to criticize the verdict for the benefit of Thailand's democracy," deputy leader Piyabutr Saengkanokkul said.

Future Forward called supporters to gather at its headquarters on Friday night. Police warned that any gathering must abide by the law.

"There have been many signs that Future Forward Party will be dissolved," said Pitch Pongsawat, an assistant professor of political science at Chulalongkorn University. "They were seen as dangerous to the establishment. The old powers did not want them to have a role in the parliament."

Supporters of Thailand's Future Forward Party react as they watch a live television broadcast of a court verdict at their party's headquarters in Bangkok on Feb. 21. © AP

Prime Minister Prayuth Chan-ocha reacted to the ruling with a tweet, asking people to "respect the court's verdict." He added that he "believe that the people who voted for Future Forward can find other alternative mechanisms to cross check the government's work."

The verdict was closely watched by Western diplomats. According to local television, representatives from the U.S., U.K., EU and Germany were at the Constitutional Court to observe the proceedings.

The European Union issued a statement after the verdict, calling the decision "a set-back for political pluralism in Thailand."

"It is important that the authorities ensure that all legitimately elected Members of Parliament are able to continue fulfilling their parliamentary mandates, irrespective of the party from the list of which they were elected," the statement says.

Future Forward ran on a platform of cutting the military budget, bringing the military under civilian control and reviewing the king's role in Thailand's constitutional monarchy. The group did well in its electoral debut, winning 80 out of 500 lower house seats. Among opposition parties, only the Pheu Thai Party, founded by supporters of former Prime Minister Thaksin Shinawatra, won more.

Future Forward later lost four seats, including Thanathorn's. The court ruled in November that Thanathorn failed to sell off his media shareholdings soon enough to serve in parliament. Some members were expelled from the Future Forward for repeatedly voting against the party line.

Future Forward's strong democratic stance was taken by some as a challenge to Thailand's current political system. In January, the court rejected another petition by the commission, which claimed the party was trying to undermine the country's constitutional monarchy.

That petition said Future Forward's website did not clearly state whether its goal was democracy, or democracy with the king as the head of state. The petition also hinted that the party has links to the Illuminati, which conspiracy theorists claim is a secret society bent on overthrowing monarchies.

The judgment will significantly shift the balance of power in the parliament. Before the verdict, the ruling coalition, which supports the pro-military cabinet, held 259 seats, while the opposition had 241 in the lower house.

Future Forward members must now find another party within 60 days or they will lose their seats.

The latest ruling is the second time the Constitutional Court has dissolved an opposition party since Prayuth has been prime minister. Last March, just ahead of the general election, the Thai Raksa Chart Party, which was closely allied to Thaksin, was ordered to disband for nominating King Maha Vajiralongkorn's older sister, Princess Ubolratana, as its candidate for prime minister. The court ruled that the party had breached a long-standing tradition placing the monarchy above politics.