Venezuela's National Guard has clashed with opposition demonstrators who were marching on the headquarters of the country's election commission, the BBC reported Thursday.

Army and police officers used tear gas and blocked roads leading to the building in Caracas.

Earlier this month, the opposition presented a petition with 1.85 million signatures calling for a referendum on Nicolas Maduro's presidency.

It wants to put pressure on the authorities to speed the process up.

The march was organized by the opposition MUD (Democratic Unity Roundtable) party.

It is demanding that the authorities verify the signatures and go ahead with the process. 

Under Venezuela's constitution, presidents can be removed from office by means of a referendum once they have served half their term.

Maduro took office in April 2013, after defeating Mr Capriles in a closely-fought election.

Source: MENA