(CNN) -- Mexican President Felipe Calderon promised federal aid to three states after torrential rains soaked the area, leaving at least 15 dead and forcing the evacuation of thousands.
The latest tropical depression comes on the heels of Hurricane Alex, which pounded the region last week. The states of Nuevo Leon, Tamaulipas and Coahuila started cleanup efforts Thursday as Calderon pledged his support at a news conference.
Nuevo Leon was the most affected, with the15 fatalities from the state and at least 43 municipalities declared states of emergency.
Many key intersections and highways throughout the state, particularly in and around Monterrey, were closed because of mudslides, according to state-run Notimex.
The national defense secretary and other federal agencies have established more than two dozen shelters in the three states, evacuated nearly 10,000 people and provided accommodations for at least 4,030.
The number of fatalities in other states was not immediately available.
Calderon said the government will provide "unconditional support" to the states as they start cleanup efforts.
"We will spare no effort to support the people that have suffered the effects of this phenomenon, Hurricane Alex, that has been the worst natural disaster in recent memory that Monterrey has suffered in particular and that the northeast has suffered in general," the president said.
In the state of Tamaulipas, the Interior Ministry issued a natural disaster declaration for 19 municipalities. It allows the state to access resources from the natural disaster fund, the ministry said in a news release.
At least 16 municipalities in the state of Coahuila are under a state of emergency as well, the national defense secretary said.
Calderon surveyed the areas aerially, and federal and local authorities continue to assess damage and provide support to the affected regions. Red alerts have been issued in locations near major rivers as waters continue to rise.
Agencies have also teamed up to conduct medical evaluations, and provide hot meals and water to those in the hardest-hit areas, the national defense secretary said in a news release.
Military forces have been working around the clock to clean up debris from roads and homes.