The rubber raft flipped over and all nine of its occupants were swept away in the cold, fast-flowing water.

The body of a 10-month-old baby was recovered and three other migrants were feared drowned after their raft capsized near Rio Grande, Texas, as they tried to cross the US-Mexico border.

The rubber raft flipped over on Wednesday night and all nine of its occupants were swept away in the cold, fast-flowing water, according to the father of the dead child, US Border Patrol said in a statement.

The father swam to safety. A Border Patrol agent jumped into the river and rescued his wife and six-year-old son. The boy was given emergency care and then rushed to a hospital for advanced treatment.

Another man and his son were found on the river bank.

The missing were believed to include the seven-year-old nephew of the dead child’s father, a girl and an adult male, according to the statement.

“What we’re dealing with now is senseless tragedy,” said Del Rio Sector Chief Patrol Agent Raul Ortiz in a statement.

The baby’s body was found several miles downriver by a Border Patrol search-and-rescue team.

Drownings are common on the Rio Grande, which makes up part of the US-Mexico border, as migrants try to cross on often overcrowded, makeshift rafts with no life jackets.

But rescues have increased since October as record numbers of Central American families try to enter the United States.

In the Del Rio sector alone, Border Patrol has rescued more than 200 people since October, a more than 800 percent rise from the year-earlier period.

Up to Thursday, the sector had recorded five water-related deaths in that period, according to sector data.

In the past seven months, Border Patrol has apprehended over 418,000 migrants on the southwest border, already surpassing the 2018 fiscal-year total.

Most of those arrested were Central American families, many of them crossing the border in large groups that can number over 400 people.

Toll greater than reported

US Customs and Border Protection recorded 283 deaths on the border in 2018, ranging from heat-related fatalities to drownings. That was down from a high of 492 in 2005 when annual apprehensions stood at nearly 1.2 million.

Migrant advocates say the death toll is far greater as many bodies are never recovered from deserts and the Rio Grande.

Last month, President Donald Trump again threatened to close the US border with Mexico, this time calling on Congress to take action.

“Congress must get together and immediately eliminate the loopholes at the border!” Trump tweeted. “If no action, border, or large sections of border, will close. This is a national emergency!”

In February, Trump declared a national emergency to circumvent Congress in obtaining billions of dollars to build his promised wall on the US-Mexico border.

Congress passed a bill to revoke the order, but Trump vetoed the measure. The emergency is also being challenged in the courts.

Thousands of people fleeing Honduras, El Salvador, Guatemala and elsewhere have made their way to the border in recent months with the hopes of applying for asylum.

Dozens have told Al Jazeera they are fleeing political persecution, violence and extreme poverty.