By Diego Oré
MEXICO CITY (Reuters) -A large migrant caravan comprising many Central Americans and Venezuelans left southern Mexico on Monday for the United States, organizers and officials said, as Washington grapples with renewed pressure on its southern border.
Officials in the southern state of Chiapas said some 3,500 people set off on foot from the city of Tapachula near the Guatemalan border, while one of the caravan's organizers, Irineo Mujica, said there were around 5,000 in the group.
U.S. President Joe Biden, who is seeking reelection next year, is under pressure to curb the number of people crossing illegally into the United States from Mexico.
Most of the latest caravan are from Cuba, El Salvador, Guatemala, Haiti, Honduras and Venezuela, according to Mujica.
Escorted by civil protection officials and ambulances, the migrants were walking on a coastal highway around midday, planning to spend the night in the municipality of Huehuetan, about 16 miles (25 km) north of where they started.
Mujica said the migrants opted to leave Tapachula due to frustration about not being able to obtain humanitarian visas. Some migrants even offered to help recovery efforts in the port of Acapulco, which was devastated by a hurricane last week, but did not get a response from the authorities, he added.
The government's National Migration Institute did not immediately reply to a request for comment.
Many migrants are fleeing poverty and political instability in their homelands, and this year has seen record numbers crossing the Darien Gap region connecting Panama and Colombia.
Millions of Venezuelans have left home due to the economic crisis plaguing the once-prosperous oil producing country.
"In Venezuela things are very tough, we can't live with the money we get, it's not enough for us, and that's why we're going to the United States," said Oscar Gutierrez, a Venezuelan migrant traveling with his wife and two daughters.
Tropical storm Pilar formed off Central America in the Pacific on Monday, and threatens to dump heavy rain on the region and parts of southern Mexico.
(Reporting by Diego Ore; editing by Jonathan Oatis)