Last month President Barack Obama began to fill some upcoming Cabinet vacancies when he nominated Massachusetts Senator John Kerry for Secretary of State. On Monday, he worked toward filling another one when he tapped former Senator Chuck Hagel for Secretary of Defense, reports The Associated Press.

The official announcement of Hagel's nomination confirms rumors that have been circulating for the last several weeks. Analysts say the choice is an interesting one given that Hagel, a Republican, may face a tough road to confirmation due to concerns from his own party on his stance toward Iran and Israel. However, he has an exemplary record and worked with Obama when they were both in the Senate.

"Chuck Hagel is a tremendous patriot and statesman, served incredibly in Vietnam, served this country as a United States senator," Sen. Heidi Heitkamp, a Democrat from North Dakota, said on ABC's "This Week."

Along with Hagel's nomination, Obama also announced he would ask John Brennan to head the Central Intelligence Agency (CIA). Brennan, who is currently a national security advisor to the president, spent more than 25 years working in the CIA.