Pope Francis has celebrated a mass for hundreds of thousands of faithful in East Timor, rallying nearly half the population of the world’s most Roman Catholic country outside the Vatican in stifling tropical heat.

Pilgrims clamoured to catch a glimpse of the 87-year-old pontiff who appeared in good spirits on Tuesday, greeting him with a rapturous reception in a wide coastal area of the capital Dili.

Approximately 600,000 people out of a population of 1.3 million attended the mass, the Vatican said in a statement, citing local authorities, in the biggest turnout for a papal event by population proportion outside the Holy See.

“I am so happy for everyone in East Timor. Now I want to see Papa Francisco here and give my present to Papa Francisco. I am so emotional,” said Mary Michaela, 17, who attended the service.

The mass was the main event of the third leg of Francis’s 12-day Asia Pacific tour, which has already taken in Indonesia and Papua New Guinea, and will conclude in Singapore.

Francis used it to hail East Timor’s birthrate.

“How wonderful that here in Timor-Leste there are so many children. We can see every corner of your land teeming with life,” he said.

He then went off-script once the mass ended, turning to the country’s rising rate of crocodile attacks to seemingly make a point about imposing values on other nations.

“Be careful, because I was told that crocodiles are coming to some beaches,” he told the crowd.

“Be attentive to those crocodiles that want to change your culture, your history. And stay away from those crocodiles because they bite, and they bite a lot.”

As night fell, the elderly pontiff toured the crowd in his popemobile as the crowd shouted, “Viva Papa Francesco!”.

Many pilgrims had arrived hours before his address to get a prime spot, waiting in the heat.

They held white-and-yellow Vatican umbrellas to protect themselves from the glaring sun, while firefighters sprayed devotees with water.