Pyongyang, August 23 (KCNA) -- Colombian President Juan Manuel Santos, in a speech made during his visit to Argentina on Thursday, called for unity of South American regional countries.

The world economic crisis will have a serious negative influence on South America, he said, urging the regional countries to unify their positions in the face of the current economic woes.

The efforts of the Union of South American Nations (UNASUR) to tide over the crisis are of weighty significance, he said.

He called for strengthening trade, investment and production within the region.