UPDATE 1-Soccer-Libertadores games involving Mexican teams off

* San Luis and Guadalajara cannot play in Colombia

* South American Confederation searching for solution

* For full coverage of the flu outbreak, click [nFLU]

(updates with Chile refusal)

ASUNCION, May 2 (Reuters) - Libertadores Cup ties involving Mexican teams Guadalajara and San Luis have been postponed because of the swine flu outbreak and Colombia's refusal to act as an alternative venue.

The South American Football Confederation (CSF) had announced the two Mexican teams would stage their home ties in Bogota but Colombian authorities rejected the plan.

On Saturday, the Chilean government also ruled out Santiago as a venue. San Luis are due to host Uruguayans Nacional on May 6 in their second round first leg and Guadalajara were scheduled to play Brazilian champions Sao Paulo the same day.

"The confederation wants to analyse, mull over the situation and find a way out," CSF spokesman Nestor Benitez told Reuters. "I wouldn't want to speculate over the outcome.