NEW YORK, May 31 - The U.S. ambassador to the United Nations on Tuesday said the Biden administration supports the shipment of Russian grain and fertilizer to address increasing global food insecurity sparked by the war in Ukraine.

Linda Thomas-Greenfield told reporters at U.N. headquarters that there are no U.S. sanctions on Russian shipments of grain and fertilizer, but she said companies are “a little nervous” and have been holding back, The Associated Press reported.

Thomas-Greenfield said the United States is prepared to give “comfort letters” to grain and fertilizer exporters and insurance companies in an attempt to get badly needed agricultural products out of Russia.

She said the Biden administration is “very supportive” of efforts by U.N. Secretary-General Antonio Guterres to allow grain exports out of Ukraine by train and the Black Sea, as well as his work to ensure Russian food and fertilizer have unrestricted access to global markets.

A U.N. spokesman said Tuesday that Rebeca Grynspan, the secretary-general of the U.N. Conference on Trade and Development, visited Moscow on Monday and held “constructive discussions” with First Deputy Prime Minister Andrei Belousov on facilitating Russian grain and fertilizer exports.

Grynspan was in Washington on Tuesday meeting with U.S. officials, U.N. spokesman Stephane Dujarric said.

Global hunger levels are at a new high, Guterres said. He said Ukraine and Russia together produce almost a third of the world’s wheat and barley and half of its sunflower oil, while Russia and its ally Belarus are the world’s number two and three producers of potash, a key ingredient of fertilizer. (ap/ez)