By Sarah Marsh

HAVANA (Reuters) - Cuba on Thursday objected to attempts by a small group of U.S. lawmakers to prevent scheduled flights between the two countries from going ahead on security grounds, underscoring its longstanding cooperation with U.S. authorities on the issue.

The former Cold War foes agreed last year to restore scheduled commercial airline services for the first time in more than five decades, as part of a broader normalization of ties, and dozens of daily flights are set to begin within months.

But a group of mainly Republican lawmakers has raised concerns about airport security and proposed a law prohibiting flights to Cuba until they are addressed.

They introduced the bill last week despite assurances from the U.S. Transportation Security Administration (TSA) that it always ensures its standards are met.

"Our airports are safe, and not because we say it, but because the specialists of the TSA say it," Armando Garbalosa, the head of security at Cuba's civil aviation authority (IACC), told state-run website Cubadebate.

TSA officials told a House of Representatives transportation security subcommittee in May that it had enjoyed a "strong, professional relationship" with the IACC for years and the latter had been receptive to all its proposals.

The subcommittee chairman, Republican U.S. Representative John Katko, complained however he had unanswered questions and Cuba had denied him and other subcommittee members a visa to examine Cuban airports.

As a result, he introduced the bill, which would prohibit flights until the TSA certified Cuban airports had the appropriate security measures in place.

There was no indication that the measure would advance in the U.S. Congress. No vote has been scheduled in the House, and it would not have enough support to pass in the U.S. Senate.

Cubadebate suggested the lawmakers were trying to frighten Americans into not traveling to Cuba.

The number of U.S. visitors to the Caribbean island has shot up since respective U.S. and Cuban Presidents Barack Obama and Raul Castro announced a detente 1-1/2 years ago, despite an ongoing ban on general tourism.

U.S. travelers must meet at least one of 12 criteria to visit, such as being Cuban-American or taking part in educational tours or journalistic activity. The number of U.S. visitors grew 83.9 percent in the first half of this year.

(Additional Reporting by Nelson Acosta in Havana and Patricia Zengerle in Washington; Editing by Cynthia Osterman)