MEXICO CITY — Most of the thousands of migrants who left Honduras for the United States on foot last week have been turned around in Guatemala. By Tuesday morning, more than 3,000 had been detained or forcibly sent back by security forces.

Some in the caravan were aware that President-elect Joe Biden was days away from taking office in Washington and were hopeful that he would make it easier for migrants to enter the United States. But others were oblivious to the political context.

For most, it was their own plight — poverty, security threats, the pair of hurricanes that devastated the Central American nation — that compelled them to join the caravan.

The show of force by Guatemalan authorities was yet another sign of the crackdown on migration through Central America and Mexico that has intensified at the behest of the Trump administration.

For years, migrants saw joining a caravan as a safe and affordable alternative to paying a human smuggler, who might charge more than $10,000 for the journey north and mistreat them along the way. But the method no longer appears viable, as caravans now run headlong into a militarized response by Central American and Mexican security forces, under pressure from Washington and fighting a pandemic.

The most recent caravan, the largest in a year, left from a bus station in the city of San Pedro Sula in northern Honduras on Friday. The migrants included families whose homes were destroyed in the two hurricanes that swept through the country in November. Others had lost their jobs in hotels and restaurants on the island of Roatán, frequented by tourists until the coronavirus pandemic. Still others were fleeing acute threats from violent criminal gangs.

Lucy Cervello joined the group with her husband and three children from the city of La Lima.

“The hurricane destroyed everything we own. We’ve been homeless since November,” said Cervello, 32. “We don’t have enough to eat anymore. The government has done nothing to help.”

Cervello had heard migrants talk about Biden, but she didn’t know who he was or what was supposedly changing in the United States. Her daughter, Marjorie, was mourning the family’s dog, Princess, who had drowned in one of the storms.

Conservative commentators in the United States have reduced the migrants’ motivations to a pure political calculus, suggesting that Biden’s election was the major reason for the caravan’s formation. History and interviews on the ground suggest otherwise. Before the region locked down against the coronavirus, caravans formed periodically during Trump’s presidency. While they are often organized by local activists and gain steam on social media, political awareness among the groups is often limited.

The number of migrants apprehended at the U.S. border has remained relatively steady since Biden’s election, rising only slightly from 71,726 in October to 73,513 in December. Those numbers — which include multiple entries for migrants who are rapidly expelled under a pandemic-era policy and attempt to cross again — remain far below the recent spike of 144,116 in May 2019.

Before Marlon Wood left to join the group from Roatán, he posted a photo of his family on Facebook. The 23-year-old planned to find work in the United States so he could send money back to them.

“You are the reason why tomorrow I decide to leave my country to have a better life,” he wrote. “God knows my heart and knows everything I have done and suffered for you all.”

Citizens of Guatemala, Honduras and El Salvador normally enjoy freedom of movement among the three countries. But because Guatemala now requires a negative coronavirus test upon arrival, the Honduran migrants were stopped at the border. Still, most of the caravan pushed through the crossing.

Guatemala’s foreign minister, Pedro Brolo, said their entry “violated national sovereignty.”

Thousands made it across Guatemala’s border and continued north. But less than 100 miles later, they were stopped at several military checkpoints. Photos and videos showed security personnel beating migrants back with batons.

Jordan Rodas, the human rights ombudsman in Guatemala’s attorney general’s office, called the response “deplorable.”

Authorities said 3,329 people have been detained or returned to Honduras. Some smaller groups have attempted to continue north. But the chances that a substantial group could make it through not only Guatemala but also Mexico, where security forces have already deployed, were slim.

Partly in response to threats from the Trump administration, both Guatemala and Mexico have increased their efforts to combat the transit of migrants through their countries. The Biden administration has not said whether it will continue the pressure, but incoming officials have said that newly arrived migrants will not be able to immediately enter the United States to apply for asylum.

Efforts to deter caravans have also drawn domestic support in Mexico and Central America.

“Some communities had once been supportive of caravans but reached a point where it was too much,” said Maureen Meyer, vice president for programs at the Washington Office on Latin America.

“We’ve now had three caravans over the last year stopped either in southern Mexico or Guatemala, which suggests that it’s no longer as possible as it once was to travel this way,” she said. “The coordination between governments around this caravan suggests there’s not a lot of appetite within these countries for these large movements of people.”

Mexican officials say they are not stopping the flow of migrants merely as a favor to the United States, but in an effort to streamline their own migration system and minimize public health risks during the pandemic.

“We are going to continue acting the same way,” President Andrés Manuel López Obrador said Monday.

Many of the migrants are being sent back to precarious conditions. Some of the hurricane victims are living in tents provided by foreign donors; others are squatting on the floors of local schools.

“Some days we eat one meal,” said Wendy Treches, 40, the day before she left with the caravan. “Some days we eat nothing.”

She was traveling with her three children after her house in the city of Santa Bárbara was destroyed by the storms.