Filer's Federal ID # for a foreign university

An eligible educational institution is a school offering higher education beyond high school. It is any college, university, trade school, or other post secondary educational institution eligible to participate in a student aid program run by the U.S. Department of Education.

If they have a federal tax ID, you can contact them to get it. This link from the Department of Education, database of eligible institutions shows all accredited schools. If your school is found using this link, then it is an eligible institution and you can claim the American opportunity tax credit.  If it is not on the list, you cannot claim it.