Israel was aware of the letter US President Barack Obama sent secretly to Iranian Supreme Leader Ali Khamenei to ask for support in a coalition against the Islamic State, an Israeli daily reported Sunday.

Israel learned of the letter through unofficial channels before the Wall Street Journal broke the story last week, the Haaretz broadsheet reported, citing an anonymous Jerusalem official.

According to the report, Obama reached out to Khamenei last month, offering to work together fighting the Islamic State terror group in Iraq and Syria should a deal limiting Iran’s nuclear capabilities go through.

The Wall Street Journal noted that American allies in the Middle East who would have opposed the offer, including Israel and Saudi Arabia, were not told of the correspondence in advance.

In this picture released by the official website of the Iranian supreme leader's office, Supreme Leader Ayatollah Ali Khamenei, center, President Hasan Rouhani, right, and outgoing president Mahmoud Ahmadinejad, sit, in an official endorsement ceremony for Rouhani, in Tehran, Iran on Saturday, August 3. (photo credit: AP Photo/Office of the Iranian Supreme Leader)

In this picture released by the official website of the Iranian supreme leader’s office, Supreme Leader Ayatollah Ali Khamenei, center, President Hasan Rouhani, right, and outgoing president Mahmoud Ahmadinejad, sit, in an official endorsement ceremony for Rouhani, in Tehran, Iran on Saturday, August 3. (photo credit: AP Photo/Office of the Iranian Supreme Leader)

US officials have not confirmed or denied making the private request, although Khamenei claims that he had rejected a previous private approach proposing military cooperation from the Obama administration.

In the wake of the letter, US Secretary of State John Kerry denied that the US had coupled Middle East security issues together with Iranian nuclear negotiations.

“No one to my knowledge has confirmed or denied whether or not there is a letter or was a letter,” Kerry said in a news conference in Beijing, before declining to comment on the details of the president’s private communication.

US Secretary of State John Kerry (R) and Iranian Foreign Minister Javad Zarif (L) shake hands as Omani Minister Responsible for Foreign Affairs Yussef bin Alawi (2nd R) and former EU top diplomat Catherine Ashton watch in Muscat on November 9, 2014. (photo credit: AFP PHOTO/NICHOLAS KAMM/POOL)

US Secretary of State John Kerry (R) and Iranian Foreign Minister Javad Zarif (L) shake hands as Omani Minister Responsible for Foreign Affairs Yussef bin Alawi (2nd R) and former EU top diplomat Catherine Ashton watch in Muscat on November 9, 2014. (photo credit: AFP PHOTO/NICHOLAS KAMM/POOL)

“I will tell you this, though: No conversation, no agreement, no exchange, nothing has created any kind of a deal or agreement with respect to any of the events that are at stake in the Middle East,” Kerry said.

“There is no linkage whatsoever of the nuclear discussions with any other issue, and I want to make that absolutely clear. The nuclear negotiations are on their own, they are standing separate from anything else, and no discussion has ever taken place about linking one thing to another.”

According to the Wall Street Journal, the letter was the fourth between Obama and Khamenei since 2009.

Prime Minister Benjamin Netanyahu said Saturday the US should not be linking the fight against the Islamic State to the nuclear issue.

“I think the struggle with ISIS doesn’t need to come at the expense of preventing Iran from obtaining nuclear arms,” he said  before meeting with EU foreign policy cheif Federica Mogherini, according to Haaretz.