Venezuelan President Nicolas Maduro has ordered the expulsion of three US consular officials, blaming them for helping the ongoing anti-government protests in the Latin American country.

Accusing the unnamed US officials of infiltrating Venezuela's universities under the pretext of dealing with student visas, Maduro said the US was working with the opposition groups plotting to topple the socialist government.

"It's a group of US functionaries who are in the universities. We've been watching them having meetings in the private universities for two months. They work in visas," the Venezuelan leader said in a state television address.

"Venezuela doesn't take orders from anyone," Maduro added, without providing specifics of the intelligence report collected over the period.

The expulsion came a day after Washington expressed concern over the snowballing situation in Venezuela and the arrest of key opposition leaders.

Maduro said he had received a request from the US urging him to hold talks with the opposition and release the detained protesters. In response, Maduro said: "I replied that I don't accept threats from anyone in this world!"

There was no immediate reaction from the US.

Meanwhile, two key anti-government figures have called for rallies which could further escalate the unrest in Venezuela.

Harvard-educated Leopoldo Lopez, against whom an arrest warrant has already been issued prompting a statement from US State Department, has urged his supporters to join him in a march to the interior ministry on Tuesday (18 February).

"If anyone has decided to illegally arrest and jail me, you know I will be there to take on the persecution... I have nothing to fear; I have not done anything illegal," Lopez said, adding he would seek a thorough investigation into the role of government forces in the death of protesters.

At least three deaths have been reported in the last few days of the unrest with both government and the opposition pointing fingers at each other.

The opponents, citing increasing prise rise and crime rates, have been demanding that Maduro step down although there is no sign of his resignation.

Another top anti-government leader Henrique Capriles, the governor of Miranda state and the chief of opposition bloc MUD, has also called for a mass rally. It is unclear whether both the groups will hold marches on the same day.