President Barack Obama is sitting down with South Korea's President Park Geun-hye, whose attention is unavoidably split between her economic agenda with Obama and the unfolding aftermath of a tragic ferry disaster.

President Barack Obama (L) shakes hands with South Korean President Park Geun-Hye (R) before a meeting at the presidential Bule House in Seoul, South Korea (Jung Yeon-Je - Pool/Getty Images)

Arriving on Friday afternoon at the Blue House, South Korea's presidential residence, Obama presented Park with an American flag that flew over the White House on April 16 - a day of growing infamy for South Korea. Sitting down for meetings with Park, Obama expressed his condolences over the sunken ferry incident, which has consumed Park's government for more than a week as divers discover yet more bodies.

"As allies, but also friends, we join you in mourning the missing, and especially the young people," Obama said before the two leaders bowed their heads for a moment of silence.

The vast majority of the 300 dead or missing victims attended a high school near the capital of Seoul. Most of the ferry's 29-person crew survived, but 11, including the captain, have been arrested on suspicion of negligence or abandoning people in need as the ferry sank. Park recently blasted their actions as "tantamount to murder."

Accepting the flag from Obama, Park drew a parallel between the way Americans pulled together after 9/11 and the resilience of South Koreans in the aftermath of their own tragedy.

"The Korean people draw great strength from your kindness," she said.

The president's overnight stay here is his second stop on a four-country Asia swing that also includes visits to Malaysia and the Philippines. Obama flew to Seoul from Japan, a major U.S. ally whose relationship with South Korea has deteriorated over historical resentments stemming from World War II.

Playing something of a mediator, Obama brought Park and her Japanese counterpart together for a trilateral meeting last month in Europe, and the president was expected to follow up on those discussions while in South Korea.

After arriving on Friday afternoon, Obama headed first to the National War Memorial, where he laid a wreath in honor of victims of the Korean War and led a naturalization ceremony for 20 military service members and their spouses from 14 countries. He used the occasion to call for a comprehensive immigration overhaul in the U.S., saying he's going to "keep pushing to get this done this year."

Obama's motorcade later rolled through downtown Seoul, past a stream lined with yellow ribbons in honor of the ferry victims. He arrived at the Gyeongbok Palace, a sprawling compound with an imposing pagoda-like structure in the center where the president got a tour.

In an interview with the South Korean newspaper JoongAng Ilbo, Obama acknowledged that he is arriving at a difficult time for the country but said the visit will give him a chance to express the American people's sympathies. He noted that U.S. military personnel, who number about 28,500 in South Korea, are part of the search and rescue operation.

White House officials said Obama did not plan to alter his itinerary because of the disaster, but would probably soften warnings he had been expected to deliver about North Korea and tensions in the region with words of condolence for the ferry victims and the South Korean people.

Still, concerns about North Korea and its nuclear program were not far from the forefront. While in Seoul, Obama was to receive a military briefing at Yongsan Garrison, where U.S. operations in South Korea are headquartered.

Pyongyang threatened last month to conduct a fourth nuclear test, possibly while Obama is in the region. The White House said it was keeping close tabs on activity at the North's nuclear test site, where commercial satellite imagery this week showed increased activity.

Obama told the South Korean newspaper that another test would gain North Korea "absolutely nothing" but deeper isolation from the world. He said such a test would meet a "firm response" from the international community, without specifying the response.

Obama will also renew his plea for countries in the region to de-escalate multiple territorial disputes with China, officials said. Seoul's key concern is about an area in the East China Sea that is effectively controlled by South Korea but falls within a controversial air defense zone that China created last year.

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