(Credit: Winslow Townson/AP Photo)

Twice in as many days, Vice President Joe Biden did something Obama administration officials rarely do - apologize for offending a foreign leader.

Biden called Turkish President Recep Tayyip Erdogan on Saturday and Crown Prince of Abu Dhabi Mohammed bin Zayed Al Nahyan on Sunday to try to quell an international diplomatic furor he created during a speech at Harvard on Friday, according to the White House.

Biden had suggested that several Arab state allies of the U.S. in the Middle East, including Turkey and the UAE, are the "biggest problem" in the effort to combat Islamic extremists in Syria. He said the countries had "poured hundreds of millions of dollars and tens of thousands of weapons into anyone who would fight against [Syrian President Bashar] Assad. Except that the people who were being supplied were [Jabhat] al-Nusra and al-Qaeda."

Biden Apologizes to Turkey President in Phone Call

Biden Calls UAE Prince to Clarify Remarks on Syria

Biden also claimed that Erdogan conceded to him privately in a recent conversation that Turkey had erred in allowing insurgents to flow across its border into Syria.

The comments drew a swift rebuke from Turkish and Emirati authorities, injecting new tension to relations at a time when the U.S. is courting their support in the fight against ISIS.

Biden "wanted to clarify that his recent remarks regarding the early stages of the conflict in Syria were not meant to imply that the UAE has facilitated or supported ISIL, al-Qaida or other extremist groups in Syria. And that was the message that he conveyed," White House spokesman Josh Earnest said of the call to the crown prince.

He added that Biden's conversation with Erdogan apologized for "mischaracterizing the president's views in a private conversation."

The White House does not outright deny, however, that the substance of what Biden said was true - that Arab states are partly responsible for fueling the rise of ISIS, a point which President Obama made publicly earlier this year, though he did not identify specific countries by name.

As for Biden's standing in the White House after a recent string of gaffes, Earnest said the vice president remains a treasured "core member" of Obama's team.

"The vice president is somebody who has enough character to admit when he's made a mistake," Earnest said. "He did that both publicly … when his office generated readouts of these calls, but he also did it privately when he took the telephone to clarify and apologize for his comments over the weekend."

No word on whether Biden apologized to Obama.