ANNAPOLIS, Md. (AP) — Maryland’s two U.S. senators are introducing a measure to prohibit foreign adversaries from owning or controlling companies that support election systems.

Democratic Sens. Chris Van Hollen and Ben Cardin said Thursday they were introducing the bill, along with Republican Sen. Susan Collins, of Maine.

The measure comes after the FBI told Maryland officials in July that a Russian oligarch with close ties to Russian President Vladimir Putin was heavily invested in the software vendor that maintains key parts of Maryland’s election infrastructure.

Before the FBI briefing, state officials were unaware that the vendor, ByteGrid, is financed by AltPoint Capital Partners, whose largest investor is a Russian oligarch. ByteGrid has said the company’s investors have no involvement or control in company operations.

The measure includes public disclosure and annual reporting requirements.