The Federal Emergency Management Agency is sending teams to Mississippi to begin joint damage assessments with MEMA, local officials and members of the Small Business Administration, according to MEMA.
There were at least 80 people injured, two critically, but no reported deaths from the storms, according to MEMA.
After assessing the damage Monday, the National Weather Service increased the rating of Sunday's tornado in Hattiesburg to an EF-4 with maximum sustained winds of 170 MPH. The increased rating is due to the damage around Oak Grove High School and a housing area just to the southwest of there.
Another tornado in Marion County was rated an EF-2. That tornado spun off from the Hattiesburg tornado.
The Salvation Army is asking for donations to help those recovering from the tornadoes.
"We are in need of donations to support our response to the Hattiesburg tornadoes," writes Divisional Communications Director Mark D. Jones with the Salvation Army.
People interested in volunteering to assist with the clean-up are encouraged to sign up on the Mississippi Commission for Volunteer Service website or by calling 1-888-353-1793.