Trump thanks troops by phone, hints he might visit Afghanistan war zone

The president has yet to visit troops in a war zone during his first two years.

Speaking to the commander of Bagram Air Field in Afghanistan Thursday, he asked, "How are things going over there?" and later said, "Maybe I'll see you over there. You never know what's going to happen."

Asked by a reporter if he wants to go, Trump said, "We'll be doing some interesting things." When asked: "Do you know when?" Trump responded, "I do, but I can't tell you."

On Tuesday, Trump was asked as he departed the White House whether he was "afraid" to visit the troops in a war zone, after the Washington Post reported that a former senior White House official had said Trump was "afraid people want to kill him."

“No," Trump responded. "I’m going to a war zone.”

He was also asked why he hadn't visited a war zone while president in an interview on "Fox News Sunday."

“There are things that are being planned. We don’t want to talk about it because of--obviously because of security reasons and everything else,” Trump said. “But there are things that are planned. As you know, I was very much opposed to the war in Iraq.”

Defense Secretary James Mattis said Wednesday he has advised the president not to go certain places at certain times.

“The president’s the commander in chief and he decides where he needs to go,” Mattis said. “There are times I don’t want him in certain locations to be frank with you, for his security and the troops’ security.”

One year ago, Trump kicked off his first Thanksgiving as president with remarks to the troops via videoconference from Mar-a-Lago. He thanked them for their service and praised progress in the fight against ISIS, as well as the domestic economy and the “big, fat, beautiful tax cuts” on the way.

In 2003, President George W. Bush surprised troops in a war zone on Thanksgiving Day. That was 15 years ago -- the same year he deployed those troops to fight.

It has not been done on a holiday since. Obama visited a war zone five times during his presidency and he did so within the first four months of his first term.

When Obama visited Iraq in April 2009, there were close to 140,000 U.S. troops in the country. He had campaigned on ending the Iraq war -- and during that trip, he officially announced a strategy for U.S. withdrawal. Today, there are 5,200 U.S. troops in Iraq.

When Obama first went to Afghanistan in March 2010 he had just announced a surge of another 30,000 troops back to that forgotten, nine-year-old war. The number of U.S. troops in Afghanistan would grow to 100,000 later that year. Today, there are 14,000 U.S. troops in Afghanistan.

There are also 2,000 U.S. troops in Syria.

ABC News' Elizabeth McLaughlin contributed to this report.