Tens of thousands of US-bound migrants and refugees have gone missing while crossing borders, rights groups say.

Puebla, Mexico – Edgar Rodolfo Xon Ajanel called his mother just before he was set to cross the border from Mexico into the United States more than 10 years ago.

The call came from Matamoros, just south of the border from Brownsville, Texas, on July 22, 2008.

“He said he was minutes away from crossing,” Sofia Sebastiana Xon, one of Edgar’s younger sisters, told Al Jazeera.

“That was his last call.”

Xon was only nine years old when her brother left the family home in Chichicastenango, a mostly Indigenous Maya Kiche town in the Quiche department in Guatemala. Edgar, then 22, wanted to find work in the US to support his five younger sisters and their mother.

Before leaving, Edgar worked as a street vendor in Chichicastenango and all over Quiche. But sometime after his father abandoned the family, he became the sole breadwinner and his earnings were not enough to feed the family.

Edgar paid a smuggler to take him over the border but they never found out whether or not he made it into the US, Xon said, speaking softly while fidgeting with the large laminated photograph of her brother she wore around her neck.

The photo was one of many worn by family members in Puebla this week as part of an annual caravan of Central American Mothers of Disappeared Migrants.

{articleGUID}

Tens of thousands of migrants and refugees have disappeared while travelling north through Mexico to the border with the US, according to human rights and migrant support groups.

[Sandra Cuffe/Al Jazeera]

Many Central American migrants simply lose contact with their families along their northbound journey, but others are believed to have died either at the hands of organised crime groups or security forces or from dehydration or exposure to the elements, among other conditions.

In most cases, families of the disappeared never find out what happened.

Every year since 2004, Central American mothers and other relatives spend two weeks travelling thousands of kilometres in Mexico to search for their loved ones, raising awareness, and speaking out for radical changes in border and immigration policies.

{articleGUID}

This year was Xon’s second time participating in the mothers’ caravan.

She stepped off the group’s bus in Puebla to cheers, drumming and applause from members of dozens of local activist collectives, migrant support groups, feminist and student associations, and others who arrived at a city market to hear from the women from Guatemala, Honduras, El Salvador and Nicaragua searching for their loved ones.

The caravan is organised by the Mesoamerican Migrant Movement, a grassroots network coordinated in Mexico but with ties throughout Central America.

Much of the network’s work is focused on attempting to locate migrants and refugees who have disappeared in Mexico and reunite them with their families. Sometimes they succeed. But often, they do not.

Women of the Caravan of Central American Mothers hold up photos of missing migrants as they visit the Basilica de Guadalupe during their journey searching for relatives [Carlos Jasso/Reuters]

The movement also coordinates Puentes de Esperanza (Bridges of Hope), a project in which Mesoamerican Migrant Movement members travel the migrant trail in Mexico, find Central American migrants who have lost contact with their families, and then attempt to track down the relatives in Central America.

This year’s caravan participants met mothers of disappeared migrants from Mauritania, Senegal, Morocco and other countries, forming global network.

Ruben Figueroa, the movement’s coordinator for Central America and southeastern Mexico, called the meeting significant, adding that the group issued a declaration, which stated that the “process of forced displacement all over the world has obligated people to leave their place of origin, their country, and their loved ones behind”.

‘Just want to cry’

The mothers of disappeared migrants from the Americas, Africa and Europe urged governments worldwide to respect international law with regard to asylum, refugees and the treatment of migrants.

{articleGUID}

“Nothing can stop a mother who is searching for her son or daughter. Mothers will bring down all the barriers and cover all the kilometres they need to until they arrive at the truth,” the mothers noted in the declaration.

Siblings often do the same. Like Xon, Marcela Melchor has been searching for her sister for a decade. Her sister Izabel Melchor Ramos called home to wish their mother a Happy Mother’s Day in May 2008. It was her last call.

“She always communicated by phone, but from public phones in Mexico,” Melchor told Al Jazeera.

The Indigenous Maya Kiche sisters are from Ixcan, in the northern reaches of the Quiche department of Guatemala.

A single mother, Izabel first left home to work in a garment factory near Guatemala City to support her three children, but it became unsafe.

“There is a lot of crime. When she would leave work, she was followed and hassled,” said Melchor, wearing her sister’s photograph at the mothers caravan event Tuesday in Puebla.

Men line up for a meal as posters for the missing line a window at a shelter for migrants in Tijuana, Mexico [Gregory Bull/AP Photo]

Izabel came home and then set out in January 2008 for Mexico to search for a job. She worked at a restaurant in Cancun for a while, but her last call home in May of that year was from the state of Chiapas in southern Mexico.

At the time, Izabel’s three daughters were eight, 10 and 12 years old. She left them in her sister’s care.

“They call me mama tia [mom-aunt]. I raised them,” said Melchor.

{articleGUID}

The entire family continues to search for Izabel. They found help from local associations in Ixcan, then from a Guatemala City organisation, and then from the Mesoamerican Migrant Movement.

Melchor feels good to be with other women in similar positions on the mothers caravan, but focusing on so many stories and cases of disappeared migrants while covering more than 5,000km from home to and around Mexico and back is hard, she said.

“Sometimes there are moments of smiles, but sometimes you just want to cry,” said Melchor.

‘Looking to survive’

This year the mothers caravan overlapped with the ongoing exodus of thousands Central American migrants and refugees, in large groups also called caravans, heading north through Mexico to the US. Aware of the stories of violence and disappearances, the migrants and refugees are sticking together for safety in numbers.

An initial wave of more than 1,000 Hondurans left their country last month, mainly fleeing violence, repression, poverty and unemployment. The group quickly grew to more than 5,000 people,

Thousands of Central Americans, mainly Hondurans and Salvadorans, have left in subsequent caravans and are heading north behind the first group, which is currently in Mexico City. An estimated 12,000 Central Americans are making the trek north en masse in large, visible groups.

Central American migrants cross the Suchiate river, the natural border between Guatemala and Mexico, to reach the US [Carlos Garcia Rawlins/Reuters]

The caravan of Central American relatives of disappeared migrants first met up with the first group of thousands of migrants and refugees in the state of Chiapas in southern Mexico at the outset of the mothers caravan.

If anyone has heard of my brother, if anyone knows him. Please tell us. Sofia Sebastiana Xon, sister of missing migrant, Edgar Rodolfo Xon Ajanel

Both Melchor and Xon told Al Jazeera they felt sadness when they witnessed the size and conditions of the group and heard some of the individual stories of participants. For Xon, it reminded her of her brother Edgar and why he left a decade ago.

“They’re looking for a way to survive,” said Xon, noting the insecurity and violence in many Central American countries.

Women of the Caravan of Central American Mothers hold up photos of missing migrants as they protest against President Donald Trump’s anti-immigrant policy in front of the US embassy in Mexico City [Carlos Jasso/Reuters]

Asked if she wanted to add anything before the mothers caravan took off from Puebla to its next stop in Oaxaca on the way home to Central America, Xon began reeling off the basic details that could help identify her brother.

It was clear she has had practice reciting the litany of information.

Edgar is 1.62 metres tall. He was 22 when he went missing, so would now be 32. His last known location was Matamoros. He has birthmarks on his nose and cheek, both on the left side, Xon continued.

“If anyone has heard of my brother, if anyone knows him,” she pleaded. “Please tell us.”