Power struggle deepens

• Bolton cancels South Korea trip 'to focus on events'

• UN condemns use of force after troops kill 2

• After Brazil, Venezuela seals Colombia border 

Venezuelan security forces fired tear gas and rubber bullets yesterday to disperse a crowd demanding to cross the Venezuela-Colombia border, ordered closed by President Nicolas Maduro as tensions in the Latin American country soared ahead of an opposition deadline to bring in humanitarian aid.

"We want to work!" people chanted as they faced Venezuelan National Guard riot police blocking the crossing at the Urena border brige to Colombia, one of several ordered closed Maduro late Friday.

Meanwhile, four National Guard troops deserted their posts near the border, one greeted by a crowd of cheering Venezuelans on the Colombian side as he walked across. Three others smashed through a security barrier on the Simon Bolivar bridge crossing in their jeep.

Supporters of opposition leader Juan Guaido in Colombia are planning to cross the border carrying emergency supplies into Venezuela later yesterday. Guaido has vowed humanitarian aid would enter his country despite a blockade.

Socialist leader Maduro has rejected the aid, which he's dismissed as a show and pretext for a US invasion.

Humanitarian aid has become the centerpiece of the stand-off between Maduro and Guaido, the 35-year-old leader of Venezuela's National Assembly who declared himself interim president exactly one month ago. Guaido has accused Maduro of rigging his re-election and is demanding a new vote.

Guaido on Friday defied a government ban on leaving the country and attended the "Venezuela Live Aid" concert organized by British billionaire Richard Branson just over the border in Colombia. The concert is aimed at raising funds to help the relief effort.

Guaido sensationally claimed that the Venezuelan military, whose high command has repeatedly declared absolute loyalty to Maduro, "participated in this process" to get him into Colombia.

Hours later, Caracas said it had closed much of the Colombian border, citing threats to Venezuela's security. It earlier sealed border with Brazil.

On Friday the tense stand-off turned deadly when two people were killed and 15 wounded as they tried to prevent Venezuelan troops from blocking an entry point on the Brazilian border.

UN Secretary-General Antonio Guterres urged Venezuelan authorities to refrain from using lethal force against protesters.

Meanwhile, US national security adviser John Bolton has canceled his trip to South Korea next week, even as preparations ramp up for a second summit between President Donald Trump and North Korean leader Kim Jong Un.

US Vice President Mike Pence is expected to travel to Colombia on Monday in an effort to pressure Maduro to step down.

The US government also announced new sanctions to pressure Maduro as early as next week unless his military defies orders to block convoys of humanitarian aid planned for this weekend, a senior administration official said on Friday.