SEOUL, South Korea (AP) — A South Korean civic group said Monday that North Korea has rejected its offer to provide anti-malaria supplies to protest Seoul's support of fresh U.N. sanctions on the country.

The rejection could complicate efforts by South Korea's news liberal President Moon Jae-in to try to expand civilian exchanges with North Korea as a way to improve strained bilateral ties. All major cooperation programs between the rivals remain stalled amid an international standoff over North Korea's nuclear and missile programs.

In late May, Moon's government allowed the Seoul-based Korean Sharing Movement to contact North Korea. It was South Korea's first approval of cross-border civilian exchanges since January 2016.

The civic group subsequently exchanged emails with North Korea and was supposed to deliver anti-malaria items such as insecticides, diagnostic reagent kits and mosquito repellant to North Korea this week, according to group official Hong Sang-young.

But North Korea told his organization Monday that it won't allow the visit because of U.N. sanctions adopted last week that Seoul has vowed to implement, Hong said.

The U.N. Security Council voted unanimously Friday to add 15 individuals and four entities linked to North Korea's nuclear and missile programs to a U.N. sanctions blacklist. It's unclear if and how much the new U.N. sanctions would sting North Korea, which is already under multiple rounds of U.N. and other international sanctions.

Since Moon's May 10 inauguration, North Korea has test-fired three ballistic missiles in an apparent show of its resolve to expand its weapons arsenals to cope with what it calls U.S. hostility. Moon's government has said it will evaluate expanding civilian exchanges with North Korea, while sternly dealing with its missile and other weapons tests.

North Korea is pushing hard to build a nuclear-tipped missile that can reach the continental United States.