A picture of the reunion of family members from North and South Korea in 2010 is displayed at the headquarters of the Korea Red Cross in Seoul. (Ahn Young-joon/AP)

North Korea on Thursday rejected a South Korean proposal to resume reunions for elderly family members separated since the Korean War, a humanitarian program that has been on hold for more than three years.

The North’s decision adds to the challenges facing South Korean President Park Geun-hye as she attempts to promote even modest cooperation between the two Koreas. On Monday, Park had proposed holding a new round of reunions, saying that long-lost relatives needed to find “healing for their pain.”

Although Pyongyang and Seoul have ratcheted down their hostilities over the past eight months, they have shown little interest in working side by side — even on programs that both governments appear to value. In a letter sent to the South’s Ministry of Unification, North Korea said Park had made a “good offer” but one that betrayed the South’s “present stance of confrontation.”

“In South Korea, one war drill is being followed by another,” the North said in a statement released by its official news agency, “and huge joint military exercises are slated soon” — an apparent reference to annual springtime exercises held by South Korea and the United States.

Park had proposed that the reunions be held around the Jan. 31 Lunar New Year, a time when Korean families traditionally get together. On both sides of the demilitarized zone, tens of thousands of relatives have gone more than six decades without seeing each other. In the South, about 73,000 people are on the waiting list for the reunions. Most are in their 70s and 80s.

By North Korea’s standards, the tone of Thursday’s rejection was mild and appeared to offer hope for a thaw on the peninsula, where tensions spiked in April amid a torrent of war threats from the nuclear-armed North.

“The same situation as what happened last year should not be allowed to repeat itself,” North Korea said.

But it also criticized the South for a string of unremarkable offenses, including “indiscreet” comments by “media, experts and even authorities” and a recent speech by Park that touched on the North’s weapons program and leadership turmoil. The North last month executed Jang Song Thaek, leader Kim Jong Un’s uncle and onetime protector, on charges of treason.

Park said the North had become “even more unpredictable” with Jang’s purge.