ANKARA, July 25 (Reuters) - Turkish President Tayyip Erdogan on Tuesday described his trip to the Gulf to deal with the Qatar crisis as "productive and successful", following two days of talks that appeared to yield no immediate progress towards healing the rift.

"The visits on the Gulf tour were productive and successful," Erdogan told lawmakers from his ruling AK Party at a parliamentary meeting.

"The contacts we have made during this visit have been useful, and we will continue our efforts for the stability and peace of the region with increasing determination."

Erdogan left Qatar on Monday after two days in the Gulf trying to mediate in the worst row among Arab states for years but there was no sign he had made any progress. Turkey has been Qatar's most powerful ally in the dispute.

A senior Turkish official said the results of the trip would take time to become apparent. "The role Saudi Arabia will take in resolving the issue is vital," said the official, who spoke on condition of anonymity.

"We will see that there have been advancements in some critical issues," he said. "We may see more concrete developments on these in the coming period."

(Reporting by Tuvan Gumrukcu, Orhan Coskun and Daren Butler; Writing by David Dolan; Editing by Dominic Evans) ((david.dolan@tr.com; +90 212 350 7046; Reuters Messaging: david.dolan.thomsonreuters.com@reuters.net))