The Notre Dame Cathedral is on fire in central Paris, capital of France, on April 15, 2019. A blaze broke out on Monday afternoon at the Notre Dame Cathedral in central Paris where firefighters were still fighting to put the fire under control, Paris Mayor Anne Hidalgo said. (Xinhua/Gao Jing)

PARIS, April 16 (Xinhua) -- The devastating fire at Notre Dame Cathedral in central Paris brought shock and sorrow to France and the rest of the world.

Stunned people rushed to see the huge fire that plunged the French capital into sadness. As night fell, they remained rooted behind police cordons in front and nearby the landmark monument.

"It's too hard and painful to see Notre Dame burning without being able to do anything to stop that. It's a great monument dated back to many centuries ago that we have seen ruined in few hours," Lila Tranchon, a shop seller at the capital's 4th district told Xinhua.

Videos posted on social media showed people singing religious hymns and saying prayers as about 500 firefighters were struggling to save the cathedral.

"Everything is burning, the frame, which dates from the 19th century on one side and the 13th on the other, there will be nothing left," Andre Finot, the cathedral spokesperson told French broadcaster BFMTV.

In early Monday evening, a fire broke out in the cathedral. Online footage showed thick smoke billowing from the top of the cathedral and huge flames between its two bell towers engulfing the spire and the entire roof which both collapsed later.

Several hours later, flames were still rising in the monument, but were waning, according to Paris firefighters' spokesperson.

"We now believe that the two towers of Notre Dame have been saved. We now consider that the main structure of Notre Dame has been saved and preserved," Paris fire chief Jean-Claude Gallet told reporters, adding that two thirds of the roof was ravaged. Firefighters would work overnight to completely contain the fire and manage the risk that some interior structures could collapse.

Like Parisians that have been distraught by the terrible tragedy, world leaders expressed sorrow and grief in a deluge of messages.

"Notre Dame belonged to all humanity. What a tragic spectacle. What horror. I share the French nation's sadness," tweeted Jean-Claude Juncker, president of the European Union's executive Commission.

German Chancellor Angela Merkel said the pictures of the burning Notre Dame were "horrible," and described Notre Dame as a "symbol of France and our European culture."

"The terrible news of the fire that has devastated the cathedral of Notre Dame, symbol of Christianity in France and in the world, was received in the Holy See with shock and sadness," said a Vatican spokesman.

President Emmanuel Macron promised to rebuild Notre Dame.

"Let's be proud, because we built this cathedral more than 800 years ago," he said. "We've built it and, throughout the centuries, let it grow and improved it. So I solemnly say tonight: this cathedral will be rebuilt," said Macron.

According to local media, the fire, which broke out at around 1645 GMT, may be linked to renovation works. One firefighter was seriously injured.

Paris prosecutors said police will conduct an investigation into "involuntary destruction by fire." Criminal motives have been ruled out.

Notre Dame is considered one of the finest examples of French Gothic architecture which receives about 12 million visitors every year.