By Mitch Phillips

RIO DE JANEIRO (Reuters) - IAAF President Sebastian Coe gave a ringing endorsement to the Olympic athletics program on Saturday, acclaiming a "remarkable week" that showed athletics is "alive and incredibly strong".

Speaking at a news conference ahead of the last full night of competition, Coe accepted there had been disappointing crowds and scheduling challenges but insisted increased website traffic was an indicator of sustained interest in the sport.

"This has been a remarkable week," he said. "Before tonight we have had three world records, 10 area records, nine Olympic records and 93 national records.

"Athletics here has enthralled and entertained. Our sport is alive and incredibly strong."

Pressed to address the poor crowds, which have routinely seen the 60,000 Olympic Stadium barely a quarter full in the mornings and showing many empty seats in evening sessions, Coe accepted there had been issues.

A combination of the local organizing committee and TV preferences seems to have overruled the IAAF when it came to scheduling, while ticketing prices have deterred a local audience with little tradition for athletics and few home competitors to capture the imagination.

"We have to realistic about numbers, there have been sessions where I would like to have seen more people," Coe said.

"But we have had good crowds and in the digital space, it's gone through the roof, that shows a real passion. We want to see full stadiums but it hasn’t affected the way people have absorbed the event and having some of those finals in the morning has gone down well in Europe."

Coe was asked about the extraordinary world records of Ethiopian Almaz Ayana in the 10,000 meters and South African Wayde van Niekerk in the 400.

"There have always been questions and I know that from my own experience and from athletes I've trained with," said the man whose 1981 800 meters world record stood for 16 years.

Coe said that being in the stadium on Friday when Usain Bolt secured his "triple-triple" and ninth Olympic gold medal was a memory that will stay with him for a long time.

He has been speaking with the Jamaican superstar sprinter for three years about how he can contribute to the sport after his planned retirement next year.

"I'm very keen for him to carve out some space to help us to develop the sport and not just in an ambassadorial role," Coe said.

(Editing Ed Osmond)