An al-Qaida leader in Iraq has threatened to soon carry out an attack inside "the heart" of the U.S.

Abu Bakr al-Baghdadi released an audio recording boasting that operatives from his al-Qaida affiliate are in the midst of planning a major terror operation.

"Soon you will witness them in the heart of your homeland, as our war with you has just begun, and so await them," al-Baghdadi said.

Federal and local security officials told NBC New York there are no new specific threats inside the U.S. The officials said that overseas terror leaders often make unsubstantiated claims and threats about targeting American interests. 

This latest terror threat message did not specify where or when such a plot might take place. New York, which officials say has faced more than a dozen unsuccessful terror plots since 9/11, appears not to be a target.

"There is no specific or credible threat to New York at this time," said FBI New York spokesman J. Peter Donald.

Officials have said the 2009 Zazi subway terror plot and the 2010 Times Square car bomb attempt were the most serious threats to date against the city. Both of those plots were planned with the help of al-Qaida operatives based in Pakistan. 

Al-Baghdadi – which is believed to be a pseudonym -- became head of al-Qaida in Iraq in 2010. 

The al-Qaida affiliate in Yemen has also targeted U.S. airliners using explosives hidden in underwear. That group has also plotted to bomb cargo planes using explosives hidden in printer cartridges.

In 2005, al-Qaida in Iraq had been linked to a "baby stroller" bomb threat targeting New York subways. But after an investigation, security officials determined the alleged plot to smuggle bombs onto trains hidden in baby strollers was based on unsubstantiated information from intelligence sources overseas.

In addition to threats inside the U.S., al-Baghdadi boasted that the terror group would soon carry out more attacks and assassinations inside Iraq.

As for the U.S., he said "The leader of the infidels and protector of the Cross, I say to her: Your war on the Muslims is a failure, and soon enough Allah-willing you will collapse and accept defeat."

He went on to claim terror operatives were already en route to the US. "The Mujahideen have departed to pursue your fleeing army, and they have sworn to make you face more severe punishments than those dealt to you by Osama (bin Laden)."

NBC terrorism analyst Evan Kohlmann translated al-Baghdadi's comments.