Yemen's Houthi movement could be declared a foreign terrorist group by the outgoing U.S. administration despite concerns from diplomats and aid organizations that this might hurt peace talks and humanitarian relief efforts.

Two sources with knowledge of the situation said the U.S. will declare the Houthi as a foreign terror group as early as Monday. The Houthi is a tribe in Yemen. 

The move might hamper peace talks by the United Nations and aid groups with the Houthi aimed at ending more than five years of fighting and provide supplies to suffering civilians.

A Saudi Arabia-led a coalition of nine countries from West Asia and North Africa in 2015 invaded Yemen to back former president Abdrabbuh Mansur Hadi after he was ousted by the Houthi a year earlier. The U.S. has provided support for the Saudi coalition.

The current U.S. administration, which ends Jan. 20, alleges Iran backing for the Houthi but has said it would consider exceptions and "allowances" in its designation so humanitarian aid and supplies could be delivered.

Humanitarian supplies pass through Yemen's Hodeidah port and Sanaa airport. Both are controlled by the Houthi - the de facto authority in northern Yemen. Getting aid through requires cooperation. 

Ryan Crocker, a former U.S. diplomat to several Middle East posts, said the Houthi is "an integral part of Yemeni society." He agreed the designation by the U.S. would slow peace talks.

Late last week, three people were injured in Houthi shelling in southern Yemen - including a child. Earlier last week, at least six Yemenis were killed at a residential area in the southwestern city of Taiz. 

The U.N. Office for the Coordination of Humanitarian Affairs counted around 233,000 deaths since the fighting began.