AP/Winslow Townson
Vice President Joe Biden speaks to students faculty and staff at Harvard University's Kennedy School of Government in Cambridge, Mass. Thursday, Oct. 2, 2014.
Biden's comments are causing a rift with key US allies in the fight against the group calling itself the Islamic State, also known as ISIS or ISIL.
He already apologized to Turkey over his comments, made Thursday during a question-and-answer session at Harvard University's Kennedy School of Government in Cambridge, Massachusetts.
Biden said that "our biggest problem is our allies" who are engaged in a proxy Sunni-Shiite war against Syrian President Bashar Assad.
"The Turks, who are great friends - I have a great relationship with Erdogan, whom I spend a lot of time with. The Saudis, the Emiratis, etc. What did they do?" Biden said.
"They poured hundreds of millions of dollars and thousands of tons of weapons into anyone who would fight against Assad - except that the people who were being supplied were (Jabhat) al-Nusra and al-Qaida and the extremist elements of jihadis coming from other parts of the world," he said.
The UAE's official news agency carried a statement from Minister of State for Foreign Affairs Anwar Gargash calling Biden's comments "far from the truth." The UAE Foreign Ministry said it was astonished by the remarks.
The UAE is a key Arab partner in the US-led coalition against the Islamic State group and has targeted its fighters in airstrikes in Syria. Saudi Arabia, Bahrain and Jordan also have carried out airstrikes against the group in Iraq and Syria, while Qatar has provided logistical support.
Gargash said the vice president "gave a negative and inaccurate impression" about the UAE's support in confronting the Islamic State group and terrorism. He said Biden's statement ignored the political and practical steps taken by the UAE, as well as its position against terrorism financing.
"The UAE's counter-terrorism approach reflects a pioneering national commitment that recognizes the extent of the danger posed by terrorism to the region and to its people," Gargash said.
AP
United States Vice President Joseph Biden, left, and Turkish President Recep Tayyip Erdogan meet for a bilateral meeting at the Peninsula Hotel as the 69th session of the United Nations General Assembly.
There has been no official comment from Saudi officials over Biden's comments. On Saturday, Biden called to apologize to Turkish President Recep Tayyip Erdogan, the White House said.
"The vice president apologized for any implication that Turkey or other allies and partners in the region had intentionally supplied or facilitated the growth of ISIL or other violent extremists in Syria," the White House said in a readout of the call.
"The Vice President made clear that the United States greatly values the commitments and sacrifices made by our Allies and partners from around the world to combat the scourge of ISIL, including Turkey."
The White House readout, however, did not mention Biden's comments about Turkey's border.
While speaking at Harvard University on Thursday, Biden referred to Erdogan as an "old friend" - but said Turkey's leader had admitted to him that his country had erred in allowing foreign terrorist fighters an easy route to pass in and out of Syria.
"President Erdogan told me - he's an old friend - he said, 'You're right. We let too many people through.' Now, they're trying to seal their border," Biden said.
Erdogan said he never made such an admission to Biden, and he said Biden would be "history for me" if he did not apologize.
"I have never said to him that we had made a mistake, never. If he did say this at Harvard then he has to apologize to us," Erdogan said, according to The Associated Press.
"Foreign fighters have never entered Syria from our country. They may come to our country as tourists and cross into Syria, but no one can say that they cross in with their arms."