Santos takes early lead in Colombia election

Santos led with 47.7 percent of the votes and Mockus had 22.3 percent with 6.29 percent of polling stations counted, according to electoral authorities.

Opinion polls had shown neither front-running candidate would win the more than 50 percent of votes needed to clinch outright victory in Sunday's election and they may face a June runoff to succeed President Alvaro Uribe.

A staunch Washington ally, Uribe steps down still popular after two terms dominated by his war against drug-trafficking rebels, and his pro-business approach that attracted a flood of foreign investment especially in oil and mining.

Santos, a U.S.- and British-educated economist, led early campaigning, but Mockus, the son of Lithuanian immigrants who is also a former university professor, surged with a Green Party campaign against graft and "politics as usual."

Both front-runners say they will keep Uribe's tough security and pro-market economic policies applauded by investors, and analysts see little long-term impact on the peso or local TES bonds whoever wins.

(Reporting by Bogota newsroom; Editing by Peter Cooney)