The European Parliament has asked French police to investigate an incident between two lawmakers of the U.K. Independence Party that landed one of them in the hospital earlier this month.

EU Parliament President Martin Schulz said Wednesday he had "referred this matter to the competent French authorities," especially because of "its possible criminal implications."

Steven Woolfe claims he "received a blow" from fellow UKIP legislator Mike Hookem during an argument at a meeting of UKIP parliamentarians at the bloc's legislature in Strasbourg, France. Woolfe collapsed and was hospitalized for several days. Hookem denies hitting Woolfe.

Schulz said versions of events "diverge substantially" and there appear to have been no direct witnesses.

The anti-EU party was instrumental in getting Britain to vote to leave the 28-nation bloc.