CUCUTA, Colombia (Reuters) - At least two trucks carrying food and medicine for Venezuela returned to warehouses in Colombia on Saturday after being turned back from the border by troops loyal to President Nicolas Maduro who fired teargas.

At least two trucks caught fire on the Simon Bolivar bridge linking the two countries after a convoy carrying aid was met by Venezuelan troops who repelled the attempt to cross.

As well as the two trucks that returned to warehouses in Cucuta, a further two trucks left the area of the bridge but their destination was not immediately clear, a Reuters witness said.