Lawmakers are moving in bipartisan fashion to ground Boeing 737 Max aircraft in the US.

Democratic Sens. Richard Blumenthal of Connecticut and Dianne Feinstein of California as well as Republican Sen. Mitt Romney of Utah are asking the Federal Aviation Administration to ground the Boeing 737 Max 8 aircraft until an investigation into the cause of a crash in Ethiopia is done, according to CBS News.

On Sunday, an Ethiopian Airlines flight crashed shortly after takeoff from Ethiopia's capital, killing all 157 on board. It's the second deadly crash in recent months involving Boeing's new 737 Max 8 plane. 

"Until the cause of the crash is known and it's clear that similar risks aren't present in the domestic fleet, I believe all Boeing 737 Max 8 series aircraft operating in the United States should be temporarily grounded," wrote Feinstein in her Monday letter, which was sent to the FAA. "This aircraft model represents only a small fraction of the domestic fleet, and several other countries have already taken this important step, including China and Indonesia."

Blumenthal and Romney have echoed similar concerns on Twitter.

On Monday, the FAA said in a tweet that it'll issue a Continued Airworthiness Notification to the International Community (CANIC) for Boeing 737 Max operators, which means it'll allow this model of aircraft to make flights. The FAA didn't immediately respond to a request for comment. 

Several other countries have already grounded the aircraft. On Tuesday, the UK's Civil Aviation Authority banned the Boeing 737 Max from flying in or over UK airspace, according to BBC News. China, France and Germany have also reportedly grounded the aircraft.