NEW YORK, Sept. 25 -- New York City officials on Thursday reassured the public that it was safe to ride the subways following Iraqi Prime Minister Haider al-Abadi's warning of the Islamic State (IS) network's plot to attack subways in the United States and Paris.

The IS elements captured in Iraq said the IS plotted the attacks from inside Iraq, Abadi told reporters on Thursday while in New York for the annual meeting of the U.N. General Assembly.

The Iraqi prime minister described the plot "credible" as he has "the details", saying the attackers are not Iraqis, some of them are French and American nationals in Iraq.

Iraq reportedly has shared the information about the "serious threats" with its allies' intelligence agencies, but U.S. and French officials said they had no evidence to back Abadi's remarks.

The U.S. had not confirmed any "specific threat", said Ben Rhodes, a security aide to U.S. President Barack Obama.

If Iraq has any such information, it should share that through the intelligence and law enforcement channels, he said, but adding that the U.S. will take seriously any information it is receiving.

New York City Mayor Bill de Blasio said that there is "no immediate credible threat" to the subway system.

"The NYPD Intelligence Bureau, which everyone knows has outposts all over the world and is the leader in terms of this work in local law enforcement all over the country, has assessed the statements of the Iraqi prime minister, and at this point finds no specific, credible threat," the mayor told a news conference at Manhattan's Union Square where he arrived by subway from the City Hall.

Minutes ago, New York State Governor Andrew Cuomo also rode the city's subway from the World Trade Center to Penn Station with Metropolitan Transportation Authority Chairman Tom Prendergast to reassure New Yorkers and delivered remarks at Penn Station upon arrival.

"We are aware that there is info about possible threats. There is no credible information about any specific threats to the New York City subway system," said Cuomo.

French officials said that French security services said that they have no information to confirm Abadi's remarks.

Last week, France launched its first air raids which destroyed IS targets. After the air raids, a French tourist kidnapped by militants in eastern Algeria was beheaded.

French President Francois Hollande announced on Thursday a three-day period of national mourning after the French tourist was killed.

The U.S. started its air strikes on the IS last month and it is continuing to attack IS forces in Iraq and Syria.

The U.S. Central Command said on Thursday that it has conducted 198 airstrikes across Iraq against the IS, and along with partner nations, has conducted 20 airstrikes against the IS in Syria.