President Obama is planning Sunday to make his first visit to the demilitarized zone dividing the Korean peninsula during his three-day trip to Seoul for a nuclear security summit, White House officials said.

Obama intends to use the tour of the strip of land that cuts the country roughly in half along the 38th parallel to reaffirm the United States’ security partnership with South Korea and other regional allies, the officials said. The president will also thank the 28,500 U.S. military troops stationed in the South.

“A visit by the president to see and thank the U.S. and South Korean service members makes perfect sense,” said Danny Russel, senior director for Asia at the National Security Council.

File photo of smoke bombs exploding near a South Korean army K-1 tank during a South Korea and U.S. joint military exercise against possible North Korean attacks in Paju, near the demilitarized zone (DMZ) between the two Koreas, on Wednesday, June 8, 2011. (Ahn Young-joon/AP)

But the president’s visit comes at a sensitive time with North Korea, which recently announced plans for a rocket launch to send a satellite into space. U.S. officials called the move a “direct violation” of its recent agreement to halt weapons tests in exchange for food.

U.S. analysts have said the food aid deal would almost certainly be called off if Pyongyang follows through on the rocket launch, which coincides with the 100th anniversary of the birth of the North’s first communist leader, Kim Il Sung.

Kim was succeeded by his son, Kim Jong Il, whose death last year elevated his own son, the 20-something Kim Jong Eun, into the role as the supreme leader.

Though Obama had not toured the DMZ during two previous trips to South Korea, there is ample precedent for U.S. presidents to make appearances there. George W. Bush visited in 2002, Bill Clinton in 1993 and Ronald Reagan in 1983.

Victor Cha, who oversaw Asian affairs for the National Security Council from 2004 to 2007, said presidential visits to the zone are usually intended to emphasize the alliance with the South rather than directly provoke the North.

Obama could use the occasion as “another platform to emphasize the themes of [nuclear] deterrence,” said Cha, now the Korea chair for the Center for Strategic & International Studies.

The president would not “threaten North Korea,” Cha said, but rather emphasize the need for them to “reach out” to the west.

North Korea’s nuclear weapons program is not on the official agenda of the two-day nuclear security summit Monday and Tuesday, during which more than 50 world leaders will discuss efforts to secure all loose nuclear materials and keep them out of the hands of terrorist organizations. The summit builds on the inaugural summit Obama played host to two years ago in Washington.

But the issue of North Korea’s nuclear program, as well as Iran’s bid to develop nuclear weapons, is expected to dominate the bilateral meetings between Obama and the leaders of China, South Korea and Russia.

Obama also is scheduled to hold meeting with the leaders of Turkey and Kazakhstan and give a speech at Hankuk University in Seoul, officials said. Obama and South Korea President Lee Myung-Bak will hold a joint news conference.