Storms have inundated vast areas of Mexico since the weekend, wrecking roads, destroying bridges and triggering landslides that buried homes and their occupants. (Agencies)
In the Pacific resort of Acapulco, roads became raging torrents, stranding some 40,000 tourists. Dozens of people from a nearby village are missing after a deadly mudslide.
Emergency services said heavy rains were battering the northwestern state of Sinaloa and hundreds of people had been evacuated from coastal communities.
President Enrique Pena Nieto announced he was cancelling a trip to the United Nations General Assembly in New York next week to focus on leading the relief efforts in Mexico.
"The rainfall in the last few days has been the most intense registered in history over an extended area in Mexico," Pena Nieto said.
The rain has eased in some areas, but more may be coming. The US National Hurricane Center said an area of low pressure over the oil-producing southern Gulf of Mexico had a 50 percent chance of becoming a tropical cyclone over the next 48 hours and could dump heavy rains on already flooded areas.
The risk of more downpours comes after tropical storms Ingrid and Manuel converged on Mexico from the Gulf and the Pacific over the weekend, triggering the flash floods.
Ingrid dissipated, but Manuel eventually became a hurricane before being downgraded again to a tropical storm, then a depression. Manuel is expected to dissipate in the mountains of western Mexico later on Thursday, the NHC said.
More than 1 million people have been affected across the country, and 50,000 have been evacuated from their homes.
"It's raining really heavily. I saw lots of fallen trees on my way to work," said Cristian Nunez, 26, a hotel receptionist in Culiacan, capital of Sinaloa, which Manuel hit on Thursday. "Many employees didn't make it in ... we're basically alone," he added.
Winds blew off the roofs of houses and 11 rivers in the mountainous state broke their banks. Residents waded through muddy, chest-high waters in some areas.
Further south in flooded Acapulco, which has been hit by looting, the beach resort was still reeling. Thousands of people remained trapped in the city, awaiting evacuation as airlines and the armed forces worked to get them home.
MUD BURIES HOUSES
National emergency services reported that 97 deaths had been confirmed across Mexico. Interior Minister Miguel Angel Osorio Chong later said he did not want to give a fresh update on the tally while rescue efforts continued.
Osorio Chong said 68 people were still missing after a mudslide in a remote village in Atoyac de Alvarez, a municipality northwest of Acapulco.
The government says 288 people have been rescued from the site, and about 20 bodies have been found there so far.
Hotels in the northern Pacific state of Baja California Sur, home to the beach resorts of Los Cabos, which are popular with U.S. tourists, reported rain and wind on Wednesday, but nothing like the conditions seen in Acapulco.
The storm damage follows a sharp slowdown in the Mexican economy last month, which prompted the government to cut its growth forecast for this year to 1.8 percent.
The Finance Ministry said it has some 12 billion pesos in emergency relief funds, but footing the bill is an unwelcome burden on public finances at a time when Mexico had already proposed running a budget deficit to boost the economy.
Gabriel Casillas, head of economic analysis at Banorte, said the storms could shave between 0.1 and 0.3 percentage points off gross domestic product in the third quarter if economic activity is interrupted for 10 days in 16 badly affected states.
"We haven't seen two such aggressive weather phenomena hitting at the same time in recent years," he said. "We just don't yet know how long economic activity will be knocked out."
He said he expected the additional impact to an already weak economy, coming on top of concerns about the health of the U.S. economy voiced by the Federal Reserve this week, would push the central bank to cut its benchmark rate again in October.
By Thursday evening, all Mexico's main oil export hubs along the Gulf were open, and only one port was closed to large ships.
State oil monopoly Pemex said it was sending 126,000 barrels of fuel by sea to help bring relief to Guerrero.
Earlier, Pemex said it had dispatched technicians to fix a ruptured 12-inch (30 cm) oil pipeline from the Gulf port of Madero inland to Cadereyta, which connects two refineries.
The pipeline was damaged when the Pablillo River burst its banks due to heavy rains.
Storms have inundated vast areas of Mexico since the weekend, wrecking roads, destroying bridges and triggering landslides that buried homes and their occupants.