Trump, who is visiting France with his wife Melania for the second time since becoming president, was referring to a call made by Macron on Tuesday for a "real European army".
"Faced with Russian Federation, which is near our borders and has shown it could be threatening - I want to build a real security dialog with Russian Federation, which is a country I respect, a European country - but we must have a Europe that can defend itself on its own without relying only on the United States". But he also made clear that the USA was not disengaging, declaring "we want to help".
Trump will hold talks with Macron at Elysee Palace on Saturday.
"I don't know that we're seeing each other in Paris, but we may", Mr Trump said.
Trump, however, since taking office almost two years ago, has repeatedly questioned the mutual defense pact and harshly criticized European countries for failing to meet pledges of contributions of 2 percent of their gross domestic product to the alliance.
Ending uncertainty about whether the U.S. leader would participate, chief organiser Justin Vaisse confirmed to AFP on Thursday that Trump would not attend.
Macron told Europe 1 radio that the "main victim" of the USA withdrawal from the INF accord was Europe and its security.
Macron, in the interview, also blasted Trump's recent announcement that Washington would withdraw from the 1987 INF Treaty limiting nuclear weapons that U.S. President Ronald Reagan and Soviet General Secretary Mikhail Gorbachev agreed to.More news: Florida Gives Voting Rights To Former Felons
Brexit leader Nigel Farage blasted EU Commissioner Jean-Claude Juncker in July over the "PESCO" project.
Trump has criticized existing European tariffs and regulations on autos, and has said he believes it's unfair that barriers are higher for American auto manufacturers seeking to sell in Europe.
The rationale behind the idea of creating a European army, which has been floated repeatedly through the years but has yet to materialize, is to lessen Europe's dependence on the whims of the United States politicians, Macron indicated. That effort hasn't yet yielded results, and the Trump administration has warned that countries hosting a so-called "special objective vehicle" to subvert the sanctions could face penalties themselves.
"This world needs to meet up and defend itself", he said.
Trump said that Macron "understands that the United States can only do so much".
The White House and the Kremlin had previously considered a formal meeting in Paris.
In addition to his meetings with Macron, Trump is expected to visit the Belleau Wood battlefield and American cemetery on Saturday, and speak at a Veterans Day ceremony Sunday at the Suresnes American Cemetery.