Flooding and landslides caused by Hurricane Ingrid and tropical depression Manuel have killed 21 people on Mexico's Gulf and Pacific coasts.
Thousands of people were evacuated on Sunday as the two storms flanked Mexico, with Manuel on the Pacific coast and Ingrid heading towards the eastern states.
National Independence Day celebrations were cancelled as Manuel made landfall and bands of rain from Ingrid - churning about 175 km from the Gulf coast - reached land, causing rivers and streams to burst their banks.
State oil monopoly Pemex, which has most of its installations in the Gulf, said it evacuated three platforms off the coast of Tamaulipas.
Pemex said on Twitter it also closed 24 wells in the area but a refinery in Ciudad Madero, Tamaulipas, close to where Ingrid is expected to reach land, remained open.
The combination of a tropical storm on one coast and a hurricane on the other is unprecedented, Juan Manuel Caballero, the head of Mexico's meteorological service, told a press conference.
In some areas, rainfall from the storms could total 100 centimetres, which would set records for an entire hurricane season, Caballero said.
Beach resort Acapulco in Guerrero state experienced heavy flooding and 11 people died as buildings and walls collapsed under the weight of the rain, civil protection chief Luis Felipe Puente told a press conference on Sunday.
Three more people died in Guerrero as a result of landslides.
In Puebla and Oaxaca states, four people died in building collapses and landslides, while three people died in Hidalgo state after their vehicle was carried away by a strong current.
Hurricane Ingrid, a Category 1 storm with sustained winds of 120 km per hour, was drenching Tamaulipas and Veracruz states on the Gulf coast on Sunday, sending more than 6,000 people into emergency shelters.
Ingrid is expected to bring hurricane conditions to Veracruz and Tamaulipas on Monday, the Miami-based National Hurricane Center (NHC) said.
The storm is moving west-northwest at about 9 km per hour and expected to turn west towards the coast by Monday afternoon, the NHC said.
A hurricane warning was in effect from Cabo Rojo in the north of Veracruz to La Pesca in the south of Tamaulipas.
"The centre of Ingrid should be very near the coast of Mexico within the hurricane warning area by Monday afternoon," the NHC said.
On the Pacific coast, Manuel weakened to a tropical depression on Sunday evening after making landfall, but the storm was still producing heavy rains, the NHC said.