Why Ben Carson cancelled his trip to Israel, Africa

Republican presidential candidate Ben Carson speaks with members of the media before the start of the Republican presidential debate at The Venetian in Las Vegas on Dec. 15, 2015.

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Last Updated Dec 17, 2015 12:57 PM EST

Barely a week after he announced his foreign policy trip to Israel and Africa, Republican presidential candidate Ben Carson is canceling his planned visit.

The campaign confirmed to CBS News on Thursday that the change of plans for Africa was "due to significant security concerns."

Later, at an Iowa event Thursday, Carson told reporters that "it's classified information so I'm just going to say it's too dangerous." He said that he had been looking forward to seeing a medical school (named after Carson) in Nigeria and learning more about Nigerian-based extremist group Boko Haram, but was assured that "things will happen in the future."

Carson added that he will also forego his trip to Israel.

"I'm not going to go to Israel at this time," he said. "I would've gone if I was doing it in conjunction with the trip, but you know, I've been there. I will be there in the future. I think this might be a good time to spend a little more time at home."

The retired neurosurgeon, in an attempt to bolster his international experiences, was scheduled to travel to Nigeria, Kenya, and Zambia from Dec. 27 to Jan. 3. His Israel trip was also meant to happen before the first primary caucuses in Iowa.

Carson, in announcing the trip, had told conservative radio host Hugh Hewitt that the reason for the visit was because "a lot of our policy in the future is going to affect Africa."

Going to Zambia also would have presented the opportunity for Carson to see Joseph and Luka Banda, twins who were born joined at the head. Carson separated them in 1997, and their surgery was considered to be a success. The two have grown up largely outside of the public eye.

On Wednesday, the State Department re-issued a travel warning for Israel, the West Bank, and Gaza, saying that "the security environment remains complex" in those regions.

"The security situation can change day to day, depending on the political situation, recent events, and geographic area," the warning reads. "A rise in political tensions and violence in Jerusalem and the West Bank has resulted in injuries to and deaths of U.S. citizens."

No similar travel warnings have been issued for the African countries Carson planned to visit.

Late last month, amid mounting criticism of his inexperience on foreign policy, Carson also traveled to Jordan to meet with Syrian refugees in person.

Following the visit to the Azraq camp, the neurosurgeon promoted the idea of providing more aid to Middle East nations in order to keep Syrian refugees in majority-Muslim countries, instead of having them immigrate to the United States.

CBS News' Erica Brown and Kylie Atwood contributed to this report.