Retired Marine Corps Gen. Anthony Zinni, who was picked by the Trump administration as a special envoy to resolve ongoing disputes in Qatar, has resigned.

Zinni resigned from his post at the State Department Monday due to the fact that he could not find a solution to the issues surrounding Qatar "because of the unwillingness of the regional leaders to agree to a viable mediation effort that we offered to conduct or assist in implementing," he told CBS News.

ADVERTISEMENT

A Saudi Arabia led-coalition of other Middle East countries issued a trade blockade against Qatar in 2017 over accusations that it supported terrorism, sparking a diplomatic crisis. Qatar denied the allegations, saying it assisted the U.S. and other countries in the war on terror and the fight against the Islamic State in Iraq and Syria (ISIS).

Secretary of State Mike Pompeo Michael (Mike) Richard PompeoThe Hill's Morning Report - Sponsored by The Air Line Pilots Association - Pence lauds Harris as 'experienced debater'; Trump, Biden diverge over debate prep Trump's foreign policy successes confound his detractors It's time for a Jackson-Vanik Amendment for China MORE is currently in the Middle East on an extended visit to address counterterrorism efforts and discuss the possibility of the U.S. pulling troops from Syria.

Zinni was chosen to lead the Middle East Strategic Alliance at the request of former Secretary of Defense James Mattis James Norman MattisBiden courts veterans amid fallout from Trump military controversies Trump says he wanted to take out Syria's Assad but Mattis opposed it Gary Cohn: 'I haven't made up my mind' on vote for president in November MORE, who recently left his post in the Trump administration as the Syrian pullout was announced.

Task & Purpose reports the four-star generals are longtime friends.

Zinni told the publication that while he was “disappointed” by Mattis’s exit last month, “it didn't really affect [my] resignation."

Regarding the situation in Qatar, Zinni told Task & Purpose he "just could not get the parties out there to engage in some sort of mediation process that we offered, and I felt that I couldn't do it much further."

Special envoy to ISIS Brett McGurk also left his post at the State Department following President Trump Donald John TrumpBarr criticizes DOJ in speech declaring all agency power 'is invested in the attorney general' Military leaders asked about using heat ray on protesters outside White House: report Powell warns failure to reach COVID-19 deal could 'scar and damage' economy MORE's announcement that he would be pulling U.S. troops from Syria.