Venezuela's opposition is pushing for a boycott of an upcoming vote that it dismisses as a ploy by President Nicolas Maduro to cling to power.

The opposition plastered election centres with slogans on Monday in a final week-long push to force Maduro into aborting the election.

Maduro is pressing ahead with the vote for a Constitutional Assembly on Sunday despite the opposition of most Venezuelans, a crescendo of international criticism, and some dissent within his ruling Socialist Party.

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On Monday, a vigil in honour of the people killed in months-long protests against Maduro was abruptly brought to an end after security forces broke up the gathering.

The security forces used tear gas to disperse the crowds of protesters gathered to pay their respects to those killed in the conflict.

Men could be seen throwing themselves on the ground to avoid being hit by gunshots, which could be heard in the distance.

At least one man was arrested and was taken away by police as clashes erupted near the peaceful gathering.

The vigil took place on the highway, near at the site where Neomar Lander, a 17-year-old, was killed during a protest last month.

At least 97 people have died, and thousands have been injured or detained since the anti-government protest movement began almost four months ago.

'Lawyer imprisoned' 

In another development, a Venezuelan military court ordered the imprisonment of a lawyer that congress named to a shadow Supreme Court in a swipe at Maduro, according to a rights group and an opposition leader.

Angel Zerpa went on a hunger strike after being arrested on Saturday, said Foro Penal, a group that defends political prisoners in this oil rich country that is in the throes of a political and economic crisis.

Opposition leader Henrique Capriles also said Zerpa had been imprisoned.

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Zerpa was denied the right to have a lawyer of his choice with him when he appeared before the military court, Capriles said.

Maduro warned on Sunday that 33 judges whom the opposition-controlled congress designated last week as a sort of shadow Supreme Court would be arrested.

So far, Zerpa is the only one known to have been arrested.

The opposition says the current top court is packed with hardcore Maduro loyalists.

Many of its justices were hastily appointed shortly before Maduro's ruling party lost its majority in congress in 2015 legislative elections.

Source: News agencies