ATHENS, April 15 (Xinhua) -- Greece lamented the fire devastating the Notre Dame Cathedral in the center of Paris, Greek Prime Minister Alexis Tsipras said on Monday.

"We are deeply saddened by the destruction of the Notre Dame of Paris. It is not only a national disaster for France, but the European and the world's cultural heritage. Emannuel Macron, we stand by your side," Tsipras tweeted.

"We are devastated by the huge fire at the Notre Dame Cathedral. I would like to tell my friend Mayor Anne Hidalgo that today not only Paris and France are in mourning, but the entire world," read an e-mailed press release from the office of the Mayor of the city of Athens George Kaminis.

The spire and the roof of the medieval cathedral, one of Europe's iconic monuments, has collapsed in the blaze, according to French authorities. The cause of the fire is under investigation.