The cathedral, which dates to the year 1163 and is famous for featuring in Victor Hugo's classic novel "The Hunchback of Notre-Dame," attracts millions of tourists every year.
President Donald Trump offered his condolences to Macron on Tuesday, according to White House press secretary Sarah Huckabee Sanders.
"The United States stands with French citizens, the city of Paris, and the millions of visitors from around the world who have sought solace in that iconic structure. The Cathedral has served as a spiritual home for almost a millennium, and we are saddened to witness the damage to this architectural masterpiece," the statement said.
"Notre Dame will continue to serve as a symbol of France, including its freedom of religion and democracy. France is the oldest ally of the United States, and we remember with grateful hearts the tolling of Notre Dame's bells on September 12, 2001, in solemn recognition of the tragic September 11th attacks on American soil. Those bells will sound again. We stand with France today and offer our assistance in the rehabilitation of this irreplaceable symbol of Western civilization. Vive la France!" the statement said.
Trump on Monday encouraged France to use "flying water tankers" to put out the fire. French firefighters didn't use an aircraft to dump water on the cathedral, a strategy that France's civil defense agency dismissed on Twitter.
"Helicopter or airplane, the weight of the water and the intensity of the drop at low altitude could indeed weaken the structure of Notre-Dame and result in collateral damage to the buildings in the vicinity," the agency wrote.
Later, Trump tweeted his prayers.
Parisians mourned the destruction of the city's symbolic center. The cathedral has not undergone such damage in its more than 800 year history.