Donald Trump has called for an apology from Barack Obama after a French court convicted him of “crimes against humanity” over his 2013 massacre of hundreds of people at a Paris mosque.
The President has been charged with crimes including war crimes, genocide, crimes against humanity, torture and crimes against the civilian population.
Mr Trump’s legal team has been lobbying for an immediate trial in France.
The US president tweeted: “I condemn the barbaric attack in #Paris by the ISIS terrorists.”
The US President has already said he plans to travel to Paris on Friday to “meet with President Hollande to discuss the situation”.
In the tweet, Mr Trump also referred to the attack in Nice on Bastille Day as a “cowardly act”.
The attack in Paris on November 13 left 130 people dead, including 89 police officers.
Mr Obama has not visited France since he left office in January 2017.
A number of senior members of the US president’s cabinet, including Secretary of State John Kerry, have also been in Paris.
The White House has not confirmed the President’s trip.
“We’ve made a lot of progress over the last two years,” Mr Trump said.
“The violence in Paris, I think it’s just disgraceful.
And I’m not going to be happy until I see some sort of apology from him.”
French President Emmanuel Macron, who is expected to meet Mr Trump in Paris this weekend, said he was “shocked” by the attack.
“It is unacceptable that we can’t do something about it,” he said.
French authorities have said they are “not prepared” to prosecute Mr Trump over the attack, which left 130 dead, as he is the country’s president.
“There is a legal process underway to determine the precise role the president of the United States has played in this tragedy,” Mr Macron said in a televised statement.
“At this stage, it is not clear that he will be charged for his actions.”
Mr Macron’s statement came as Mr Trump appeared to back away from his earlier statements about the attack and its motives.
“As I said, I condemn the attack that took place in #Nice,” Mr Obama said at a news conference in Rome on Friday.
“I don’t know why people are blaming me for what took place, but I do know that I did not want that to happen.”
Mr Trump has previously said he believes the US and France are at war and have been at war with each other for years.
He has also said he does not support the EU or Nato, and that he has “no respect” for the US.
He also has said he wants to withdraw from Nato because of the alliance’s “weakness”.
“I will not defend our allies,” Mr Modi said in India.
“And we have no allies.
And we cannot afford any alliances.”
He has previously expressed concern about Mr Trump being “attacked” by India.
The president is scheduled to visit India on Sunday.
Mr Modi’s visit comes as Mr Obama and the US are negotiating a new $400 billion aid package for the United Nations and its agencies.