By Michael Hernandez

WASHINGTON

U.S. President Donald Trump said Monday he would announce his decision on extending sanctions under a nuclear deal with Iran on Tuesday.

Trump said via a statement issued on Twitter he would make the announcement Tuesday afternoon from the White House.

Trump's confirmation comes just hours after he criticized former Secretary of State John Kerry for working behind the scenes with foreign officials to preserve the nuclear agreement.

Trump said the U.S. does not need "Kerry’s possibly illegal Shadow Diplomacy on the very badly negotiated Iran Deal" after the Boston Globe reported a previously undisclosed April meeting with Javad Zarif at the United Nations in New York.

Kerry "was the one that created this MESS in the first place!" continued Trump in an earlier Twitter post.

Kerry's meeting with Zarif was the second in the past two months between the former and current top diplomats, according to the Globe, which also laid out Kerry's flurry of activity with European officials.

The nuclear agreement placed unprecedented restrictions on Iran's nuclear program in exchange for billions of dollars in relief from international sanctions, but it has been cast into jeopardy by Trump who has until a May 12 deadline to decide whether he will continue to extend sanctions relief on Iran.

Should he decide against doing so, Trump would almost certainly torpedo the agreement and its nuclear-related restrictions.

All of the U.S.'s negotiating partners -- the U.K., France, Germany, Russia, China and the EU -- agree that maintaining the accord is the best way to reign in Iran's program.

Top European officials have been counseling Trump against an exit while also suggesting an openness to some kind of "side deal" Trump is seeking on Iran's ballistic missile programs and its regional activities.