Santos wins backing of Colombia's Conservatives

Presidential candidate Juan Manuel Santos of the Party of National Unity speaks during a Reuters interview in Bogota May 31, 2010.

BOGOTA (Reuters) - Already strongly favored to win the Colombian presidency, former Defense Minister Juan Manuel Santos got another boost on Tuesday when the Andean nation's Conservative party said it will back him in the June 20 vote.

Santos, a scion of an elite family, had a 25-point lead over former Bogota Mayor Antanas Mockus in a first round vote on Sunday but was around 3 percentage points shy of winning outright. The two men will now face each other again in a June 20 runoff.

Santos, a scion of an elite family, is the political heir to staunch Washington ally President Alvaro Uribe, who steps down in August.

Uribe is still popular after two terms dominated by his war against drug-trafficking rebels and his pro-business approach that attracted foreign investment, especially in oil and mining.

The Conservative Party candidate Noemi Sanin got 6 percent of the vote on Sunday, compared to Santos' 47 percent.

The endorsement may not bring him all the voters from the Conservatives who are divided over their party's support for Santos and his predecessor.

The Conservative Party for years alternated power with the Liberal Party, and as one of the coffee, coal and oil exporting nation's oldest political organizations is experienced at getting out the vote.

Party leader Fernando Araujo said a majority of the party's lawmakers decided to back Santos on the grounds he represents continuity with the Uribe government.

Uribe's U Party, headed by Santos, is the strongest bloc in the Congress and was allied with the Conservatives during his eight years in office.

Santos is also likely to seek the support of the Cambio Radical party, whose candidate German Vargas Lleras came third in Sunday's vote with just over 10 percent of the votes.

Mockus, who got an unexpectedly low 21 percent, on Tuesday said he was not seeking the support of other parties for the second round. Instead, he said, he will focus reducing abstention.

"The only alliance I will do is an alliance with the people," the Green Party candidate said.

(Reporting by Luis Jaime Acosta; Editing by Eric Walsh)