At least 100 members of the migrant caravan travelling through Mexico in an attempt to reach the United States have been kidnapped by the Zetas cartel, according to human rights officials in the country.

Fleeing gang violence and threats back home in Honduras, Guatemala and El Salvador, thousands of the migrants travelling en masse reached Mexico City on Monday and Tuesday.

But reports have emerged that a number of members, including children, have gone missing from the group. They are suspected of having fallen prey to criminal gangs, who abduct migrants in order to extort their family members.

Human rights activists and officials in the southern states of Oaxaca and Veracruz, across which the massive group of Central American migrants have trekked over the last few weeks, say that at least 100 were kidnapped in the state of Puebla and allegedly handed over to the Zetas gang.

Arturo Peimbert, the human rights ombudsman in Oaxaca, told local media that the migrants were offered rides by fruit trucks, which they took despite warnings not to, and after getting onto the trucks found themselves locked in.

“The testimonies I have heard [of those who managed to escape] was that many of those migrants were handed over to organised crime near the Federal Police base in Puebla," Mr Peimbert related.