A U.S. ship carrying thousands of tons of food aid arrived in North Korea after the impoverished nation agreed to open up to widely expanded international assistance, the U.N. food agency said Monday. The U.S. aid was not directly related to the ongoing nuclear talks between Washington and Pyongyang, according to a report of the Associated Press. The shipment came just days after North Korea delivered a long-delayed atomic declaration and blew up the cooling tower at its main reactor site. In exchange, Washington has lifted some economic sanctions against the North and said it would remove the country from a U.S. State Department list of state sponsors of terrorism. The World Food Program said the American ship that arrived Sunday carried 37,000 tons of wheat, the first installment of 500,000 tons in promised U.S. aid that will be distributed by the U.N. The total shipment will be enough for the WFP to expand its operations to feed more than 5 million people, from the current 1.2 million North Koreans getting help from outside handouts.