MIAMI - Carnival Cruise Lines, Royal Caribbean Cruises and Norwegian Cruise Line have suspended stops at Mexican ports over concerns about swine flu.

Carnival said on its Web site it has canceled all calls at Mexican ports through May 4, and in many cases will be able to substitute the canceled stop with an alternative port.

Royal Caribbean had said it was monitoring the situation but telling passengers not to worry because the outbreaks are inland, not in the Mexican coastal cities popular with cruise tourists. But later Tuesday the company said it was suspending port calls indefinitely in Mexico until more is known about the outbreak.

The move affects its Royal Caribbean International and Celebrity Cruises ships.

Norwegian is canceling Norwegian Pearl's final two calls in Mexico this week after saying earlier it was monitoring the situation.