U.S. President Barack Obama (R) debates with Republican presidential candidate Mitt Romney at the Keith C. and Elaine Johnson Wold Performing Arts Center at Lynn University on October 22, 2012 in Boca Raton, Florida. The focus for the final presidential debate before Election Day on November 6 is foreign policy. Sen. John McCain, R-Ariz., speaks to the media prior to the debate between President Barack Obama and Republican presidential candidate Mitt Romney at the Keith C. and Elaine Johnson Wold Performing Arts Center at Lynn University on Oct. 22, 2012 in Boca Raton, Fla. (credit: Joe Raedle/Getty Images)

WASHINGTON (CBSDC/AP) — Sen. John McCain claims the Obama administration might be conducting a “massive cover-up” with the deadly terror attack on the U.S. Consulate in Benghazi that killed Ambassador Christopher Stevens and three other Americans.

On CBS News’ “Face the Nation” Sunday, the 2008 Republican presidential nominee said President Obama has been incompetent with the way he has been handling the aftermath of the Sept. 11 attack.

“I don’t know if it’s either a cover-up or the worst kind of incompetence, which doesn’t qualify the president as commander in chief,” McCain said.

The Republican senator was primarily talking about statements the administration made early after the attack where U.N. Ambassador Susan Rice said the Consulate attack was a “spontaneous” event caused by the anti-Mohammed film that caused massive protests across the Middle East.

Witnesses to the attack told The Associated Press that some 150 gunmen took part in the assault on the Benghazi compound.

“We now know there was no demonstration. There was no mob,” McCain told CBS News. “So for literally days and days, they told the American people something that had no basis in fact whatsoever.”

McCain added that this might cost Obama the election.

“Nobody died in Watergate. But this is either a massive cover-up or incompetence that is not acceptable service to the American people,” McCain told “Face the Nation.” “The American people may take that into consideration a week from Tuesday.”

Last week, CBS News obtained State Department emails that provided a timeline of the events that took place at the Benghazi compound on Sept. 11.

The first email sent from the State Department Operations Center to such agencies as the White House Situation Room, the FBI and the office of the Director of National Intelligence, among others, at 4:05 p.m. on Sept. 11 stated that the Benghazi compound was under attack.

“The Regional Security Officer reports the diplomatic mission is under attack. Embassy Tripoli reports approximately 20 armed people fired shots; explosions have been heard as well. Ambassador Stevens, who is currently in Benghazi, and four COM personnel are in the compound safe haven.”

The next email, which came at 4:54 p.m., said that firing at the Consulate “has stopped and the compound has been cleared.” Officials said that a response team was on site to locate the American personnel.

The final email that came at 6:07 p.m. states that terror group Ansar al-Sharia claimed responsibility for the attack.

“Embassy Tripoli reports the group claimed responsibility on Facebook and Twitter and has called for an attack on Embassy Tripoli.”

Defense Secretary Leon Panetta has called criticism of the handling of the attack “Monday morning quarterbacking.”

(TM and © Copyright 2012 CBS Radio Inc. and its relevant subsidiaries. CBS RADIO and EYE Logo TM and Copyright 2012 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)