DETROIT  Mayor Kwame M. Kilpatrick was sent to the county jail on Thursday and will spend at least one night there as punishment for violating his bond.

Mr. Kilpatrick is fighting perjury and other felony charges, but has refused calls to resign. Judge Ronald Giles of the 36th District Court in Detroit ordered that the mayor be jailed because of a visit he made on July 23 to Windsor, Ontario, on the opposite shore of the Detroit River, for what he said was city business.

The mayor’s lawyers sought an immediate appeal, but the Circuit Court judge who will take up the matter put off a hearing until Friday morning.

Mr. Kilpatrick, 38, apologized at length to Judge Giles for violating the terms of his bond, which required court approval for any travel outside of Michigan, and he promised that he would not make such a mistake again.