The Venezuelan president has declared a state of emergency in a border region near Colombia following an attack by smugglers in which three soldiers and a civilian were injured.

Nicolas Maduro said there would be 60 days of martial law in five municipalities of the state of Tachira.

He also said the closure of the border, announced on Thursday, will be extended until further notice.

Petrol and food smugglers have increasingly clashed with officers.

The BBC's Daniel Pardo in Venezuela reports that Mr Maduro said Colombian paramilitary groups regularly travel to Venezuela, generating chaos and shortages in order to destabilise the revolution.

Mr Maduro said an extra 1,500 soldiers had arrived to reinforce the area.

"This decree provides ample power to civil and military authorities to restore peace," he said in a broadcast on state television.

On Wednesday, three Venezuelan army officers and a civilian were injured in riots with Colombian smugglers.

Venezuela closed its border with Colombia for the first time last year.

Without making direct reference to Mr Maduro's recent statement, Colombian President Juan Manuel Santos said Venezuelan citizens were "always welcome".

Tensions run high along the porous 2,200-kilometre (1,370-mile) border.