U.S. President Barack Obama said Monday that effective enforcement of sanctions on North Korea is one of the key tasks facing the country, along with fighting terrorism and ensuring Iran meets its nuclear commitments.

Obama made the remark during an address at a conference of chiefs of U.S. diplomatic missions overseas, saying the U.S. should keep mobilizing the world to meet shared challenges, including strengthening international rules and norms that undergird peace and security.

"We're going to have to continue to ensure that Iran fully meets its commitments under the nuclear deal; to make sure that we're enforcing effective sanctions on North Korea; that, at our upcoming summit here in Washington, we're continuing to increase nuclear security," Obama said.

The U.N. Security Council adopted a new sanctions resolution on Pyongyang earlier this month in response to the North's nuclear and missile tests.

The sanctions, the toughest ever to be imposed on Pyongyang, require mandatory inspection of all cargo going in and out of the North and ban its exports of coal, iron and other mineral resources, a key source of hard currency that accounts for nearly half of the country's total exports.

The U.S. is putting together a package of unilateral sanctions against the North to carry out the Security Council sanctions and the recent congressional legislation tightening the screws on Pyongyang. (Yonhap)