BEIRUT - Syrian opposition leaders on Sunday dismissed upcoming parliamentary elections as a cynical attempt by President Bashar Assad to hold on to power and urged voters to stay away.

The regime has portrayed Monday's vote as a sign of its willingness to carry out reforms, while at the same time denying that it faces a popular uprising. In new violence, regime forces fired tank-mounted machine-guns at two neighbourhoods before dawn in the eastern town of Deir el-Zour, according to the Britain-based Syrian Observatory for Human Rights. No casualties were immediately reported.

The election of a 250-seat parliament comes three months after the adoption of a new constitution that allows the formation of political parties to compete with the ruling Baath party.

Assad's opponents say reforms without their input are a farce and elections cannot be held under the threat of guns. A U.N.-brokered truce last month has failed to halt a brutal regime crackdown on the 14-month-old uprising against Assad despite the presence of foreign observers sent to monitor compliance.

"We think the elections have no credibility at all in the middle of a situation where the regime is killing the population," said Bassma Kodmani, a spokeswoman for the Syrian National Council, the main opposition group in exile. "It is an insult to the democratic process."

Opposition leader Haytham Manna said, "We are against these elections because they don't have any of the characteristics of free elections." Manna heads the National Coordination Body for Democratic Change in Syria, which represents activists in Syria and in exile. Manna spoke from Brussels and Kodmani from Paris.

In Syria, anti-regime activists also said they rejected the vote and had seen very little government preparation for elections in some opposition areas.

In the southern town of Dael, residents prevented anyone from putting up election posters and instead put up photos of the 20 people from the city who have been killed in the uprising.

"They are our candidates for parliament," said Adel, a local activist, referring to the dead. He declined to give his full name for fear of retribution.

Another activist, Fares Mohammed in the town of Zabadani northwest of Damascus, said residents there would hold a general strike to protests the elections.

"Everyone here is refusing the elections," he said by phone.

Underscoring the continued violence, U.N. observers visited Zabadani and Dael on Sunday, and regime forces fired randomly into Dael after they left, injuring three people, Adel said.

Since the outbreak of Syria's popular revolt in March 2011, the regime has made a series of gestures to try to allay the crisis, but also kept up its attacks on centres of rebellion. The regime claims it is being targeted by a foreign-led conspiracy of criminals and terrorists.

The U.N. says more than 9,000 people were killed in the first year of the uprising.

In February, the new constitution was approved in a referendum. At the time, Syrian state media reported a turnout of 57 per cent. Such figures are impossible to verify, and opposition activists say they believe many participated out of fear. However, throughout the uprising, key constituencies have continued to support Assad.

The constitution allows, at least in theory, new political parties to be formed and limits the president to two, seven-year terms. Syria has been ruled by the Baath party since it seized power in a coup in 1963 and the Assad family has ruled since Bashar's late father Hafez took over in another coup in 1970.

Election officials say 11 new parties are participating in Monday's election, along with the 10 parties of the National Progressive Front, an alliance dominated by the Baath party. Election officials said nearly 15 million of Syria's roughly 23 million people are eligible to vote.

Earlier this week, the state-run news agency SANA reported that a pro-regime candidate, Abdul-Hamid al-Taha, was gunned down in the southern city of Daraa in an attack it blamed on "armed terrorists," the term the regime generally uses for opponents.

The election comes more than three weeks after an April 12 cease-fire aimed at paving the way for political talks between Assad and those trying to bring him down.

The truce, brokered by special envoy Kofi Annan, has failed to take hold, though U.N. observers say it has helped bring down the level of violence.

Regime forces continue to attack opposition strongholds and carry out arrests, while refusing to withdraw troops and tanks from the streets, as required by the Annan plan. Rebel fighters have kept up shooting and bombing attacks on soldiers.

Currently, some 40 U.N. observers are in Syria, and the contingent is to reach 300 by the end of May. U.N. officials hope the deployment of more observers will gradually calm the situation, and Annan's spokesman says the peace plan remains on track.

The U.S. government has offered a bleaker view of the plan's progress, saying it is perhaps time to seek another approach. However, the international community remains divided on Syria, and Assad allies Russia and China would likely block harsher U.N. Security Council measures.