Defense Secretary Lloyd Austin has canceled his trip to Brussels to meet with NATO ministers and work on Ukraine military aid as he remains hospitalized while dealing with complications from prostate cancer, two defense officials said Monday.Austin had been scheduled to travel to Brussels on Tuesday to attend a regular meeting of the Ukraine Defense Contact Group, a gathering of about 50 countries to coordinate military aid for Kyiv. That meeting will now be held virtually, the officials said.The officials spoke on the condition of anonymity to discuss details not yet made public.Austin, 70, was taken to Walter Reed National Military Medical Center on Sunday afternoon to address bladder issues. After further tests, he was admitted into the critical care unit for supportive care and close monitoring and has since transferred authorities to Deputy Defense Secretary Kathleen Hicks.Following the Ukraine meeting, he was to attend a regular meeting of NATO defense ministers, also in Brussels. It was not immediately clear if Hicks would attend that meeting instead.This is Austin's second hospitalization due to complications following surgery in December to treat prostate cancer.