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The 88-year-old North Korean man stretched his arms out the bus window to grasp the hands of his South Korean sister one final time before the end of rare reunions Tuesday between hundreds of family members separated for decades by war and politics.

"Brother, brother, my brother! How can I live without you?" the sister, Park Jong-soon, cried out from the parking lot at the North's scenic Diamond Mountain resort, according to South Korean media pool reports.

Wiping away tears, Pak Jong Song shouted back: "Stay healthy! We'll see each other again if we're healthy."

That may be wishful thinking. The brief, painfully emotional reunions that ended Tuesday — the first since late 2010 — are unlikely to be repeated anytime soon. While Seoul has long pushed for more such meetings, analysts say North Korea is reluctant for fear that increasing their frequency will loosen its authoritarian control and give up a coveted bargaining chip.

The two sets of reunions that started last week, which involved about 750 people from both countries, almost didn't happen. North Korea had threatened to cancel them to protest annual U.S.-South Korean military drills that began Monday, but allowed the reunions to go forward after high-level talks with Seoul. Analysts say North Korea's recent charm offensive is motivated by a desire to win outside aid and investment.

The participants had only three days to meet with relatives most of them hadn't seen since the Korean War ended in an armistice in 1953. Millions of families were separated by that conflict — and now the world's most heavily fortified border.

Both sides bar ordinary citizens from visiting each other and even exchanging phone calls, letters and emails. About 22,000 Koreans have had brief reunions — 18,000 in person and the others by video — during a previous era of rapprochement.

The reunions come amid some signs of easing animosity between the Koreas, which were threatening each other with war a year ago. But in a reminder of the lingering animosity between them, a North Korean navy patrol boat violated the countries' disputed western sea boundary Monday night, the first such incident this year. The boat retreated into North Korean waters early Tuesday after the South repeatedly broadcast warnings, Seoul's Defense Ministry said.

South Korea has long called for expanding the number of people who can participate in the reunions and holding them on a regular basis. But North Korea is seen as worrying that doing so could open the country to influence from more affluent South Korea and threaten its grip on power.

North Korea reportedly chooses only citizens seen as loyal for the reunions, while South Korea uses a computerized lottery system to pick participants. Because the reunions are held so infrequently, many of those who have applied for a chance to participate have died before getting to attend.

"We view family reunions as a humanitarian issue, but for North Korea it's also a political issue," said Chang Yong Seok of the Institute for Peace and Unification Studies at Seoul National University.

Pyongyang also wants to use the reunions as a way to win political and humanitarian concessions from the conservative government of South Korean President Park Geun-hye, which took office a year ago, Chang said. During the more liberal South Korean government rule that ended six years ago, Seoul rewarded Pyongyang with rice and fertilizer shipments for arranging the family reunions.

But now Seoul is unlikely to approve big aid shipments for more reunions unless North Korea also takes serious nuclear disarmament measures, analysts say — something Pyongyang seems unwilling to do.

On Monday, South Korea offered sending vaccines and disinfectants to North Korea after the country recently reported its first outbreak of foot-and-mouth disease since April 2011. The items would be South Korea's first direct government-level aid shipment to North Korea since 2010.

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Associated Press writer Kwon Su Hyeon contributed to this report.