WASHINGTON (CNN) -

After more than six decades of public service, Israeli President Shimon Peres paid his last official visit to the White House on Wednesday.

The Israeli leader discussed with President Barack Obama the wavering stability in the Middle East as civil uprisings in Iraq and Syria plague the region, as well as Iran's nuclear program -- an issue Israel sees as a major threat to its security.

On Iraq, Peres said, "I told the President that the best thing that could have happened was that Iraq remain a united country, but I wonder if it's possible."

"To do so, you need (to be) ready to stand a mighty army to force all the three parties together. I don't see the army to do it and I don't see the parties that will agree to it," he said, referring to the apparent collapse of the unity government in Iraq, and incursions into major cities by insurgents there.

The Israeli president said the Kurdish region of Iraq was one of the few success stories to come out of the Iraq war.

"In the present situation we have two different parts - one because the three parties are the Kurds, the Shiites and the Sunnis. The Kurds already built a state of their own. They are supported by Turkey and are basically democratic. For example, women enjoy their equal rights which it the first sign of democracy." he said.

As for the escalating tensions between Sunnis and Shiites in Iraq and Syria, the Israeli leader said he believed it should not be the role of the United States to take sides in religious battles.

"The difference between the Shiites and Sunnis is more an Arab problem than an American problem or a problem of the world, and I think the Arabs should come in and play a major role because I don't think it's for the West to decide who is the real heir of Muhammad."

Peres also expressed concern over Iran's nuclear program.

"If Iran will continue to build a bomb, the result is the Middle East will become nuclear," he said.

"The best way to reach an agreement is to follow the example of Syria -- send out the dangerous weapons of the land, don't keep it inside." Peres was referring to the United Nations' brokered program to dismantle and remove all chemical weapons from Syria.

After the meeting, the 90-year-old Peres told reporters at the White House that over his 60 years in government service he has met with 10 U.S. presidents.

"I told the President that among all of you I am the oldest man, so I met 10 Presidents. The first I met was President Kennedy. At that time the United States wouldn't agree to supply us arms. And now I come to a President who answers, really fully all the security needs of Israel."

According to his official biography, Peres served as a member of the Knesset, or Israeli parliament, for 48 years and has served as a minister in 12 cabinets, including two stints as prime minister. He was elected president in 2007.

On Thursday, Peres will be honored by Congress as the House and Senate leadership present him with the Congressional Gold Medal.