At least 30 people have been killed in ‌a deadly stampede at a historic tourist site on a Haiti mountaintop, with fears the death toll could rise.

The tragedy occurred at one of Haiti’s most popular attractions — the Laferriere Citadel — during an annual celebration of the UNESCO World Heritage site.

Students and visitors — including “many young people” — packed the early 19th century fortress, which was built between 1805 and 1820 shortly after Haiti’s independence from France.

Prime Minister Alix Didier ⁠Fils-Aimé said the stampede occurred at the entrance to the site, and that rain had ​exacerbated the disaster.

“While some people wanted to leave, others were trying to enter,” Communications minister Emmanuel Ménard said, citing early reports.

“People began pushing. Some fell, and others trampled over them. Consequently, some people died from suffocation.”

He told the AFP news agency that the death toll could rise due to the number of people reported missing.

The stampede was at the entrance to the site. Photo: Alan B Photography

Fils-Aimé expressed the government’s condolences “in the face of this painful situation”.

“The national authorities express their strong emotion and immense sadness,” he said.

“The government sends its sincere condolences to the affected families and assures them of its deep solidarity in these moments of grief and great suffering.”

Fils-Aimé urged people to be “calm and cautious” and await the results of investigations to determine the exact circumstances of the tragedy.

“In this particularly troubling circumstance, the Prime Minister and the government of the republic reaffirm their solidarity with the victims and the entire affected community,” he said.

According to its website, the citadel was initiated by Henri Christophe, a former slave and a leaders of the Haitian slave rebellion who later became the Caribbean island nation’s king.

“This mountaintop fortress was built from 1805 to 1820 in the aftermath of the slave revolution of Haiti and declaration of its independence from France,” the website says.

“It was designed as a part of fortification system, which was supposed to defend newly independent Haiti from the attacks of the French Army.”

The location on the top of a mountain, at 950 metres above sea level, was chosen to foresee and repel the attacks of the enemy.

“It is even possible to see the eastern coast of Cuba on some days.”

-with AAP