By Linda Hutchinson-Jafar

PORT OF SPAIN, Trinidad (Reuters) - Trinidad and Tobago's five-month post-election crisis moved into Parliament on Friday as lawmakers met for the first time in six months but failed to elect a speaker.

The energy-rich Caribbean nation of 1.3 million has been in political deadlock since December elections that produced 18 seats for each of the two major parties in the 36-seat Parliament.

After three hours of proceedings on Friday, the two parties failed to agree to the nomination of four people for the speaker's job.

Following the election, then-Prime Minister Basdeo Panday, leader of the United National Congress, and then-opposition leader Patrick Manning of the People's National Movement agreed to allow President Arthur Robinson to choose the next prime minister. But when Robinson picked Manning, Panday reneged on the deal and called for immediate elections.

Under the constitution, Parliament must convene six months after its last sitting or a new election must be held. The deadline is April 9, setting the stage for Friday's showdown.

The UNC, as it had threatened beforehand, on Friday sought to frustrate the process of electing a speaker -- voting not only against the names proposed by the ruling party but also those put forward by them.

"Go back to the polls," UNC members shouted each time the parliament failed to agree to the vote when it was put forward by the clerk of the house.

UNC officials contend that Parliament does not officially convene if a speaker is not chosen. The party has vowed to block the appointment of a speaker for five days to force the ruling PNM to call new elections.

Manning, now prime minister, has said he believes that merely opening Parliament, with or without a speaker, will satisfy the April 9 deadline. Constitutional experts have said the issue could end up in court.

The governing PNM reacted angrily at times to the scenes on Friday, with Sports Minister Roger Boynes shouting and accusing the UNC of acting "childishly" and punishing the country because it was no longer in power.

Earlier in the sitting, Manning gave a lengthy address on the events following the December election tie and the 10-point accord brokered between the parties to settle the deadlock.

"You can't come now and change the rules," Manning told the UNC members.

After three hours, the parliamentary clerk called for a break in the proceedings.

Outside Parliament on Friday morning, demonstrators gathered. Several dozen supporters of the ruling PNM heckled rival parliamentarians and clamored to enter Parliament, while about 100 demonstrators for the opposition UNC gathered a few blocks away.

Concerned about the potential for violence between rival supporters, police officials stationed hundreds of officers in and around the nearly century-old Red House, which was seized briefly by Muslim radicals in July 1990 in a failed attempt to overthrow the government.

Church leaders urged people to stay away from Parliament. By early afternoon, no clashes had been reported.

The former British colony has enjoyed a relatively peaceful past but it is politically divided on ethnic lines with about half of its people descended from Indian laborers and half from African slaves. Those of Indian descent usually support the UNC while the PNM draws its support from Afro-Trinidadians.