U.S. senators on Tuesday demanded tighter security in the wake of last weekend's assassination of a Minnesota state legislator and threats against members of Congress, in what one lawmaker called a "spreading virus" of political violence.

Following shootings in Minnesota, senators called for more funding for the U.S. Capitol Police to provide member security.

Threats to members of Congress are on the rise, security officials told senators at an emergency briefing in the wake of the killing of a Minnesota state lawmaker in her home over the weekend.