A federal judge has ruled that a lawyer for former President Donald Trump must provide additional testimony before a federal grand jury investigating Trump's handling of classified documents, sources familiar with the matter told ABC News.

Special counsel Jack Smith's prosecutors asked Judge Beryl Howell last month to pierce attorney-client privilege and compel Trump attorney Evan Corcoran to appear before a grand jury, sources previously told ABC News.

A Trump spokesperson didn't immediately respond to a request for comment.

This is a developing story. Please check back for updates.