Temporary visas will be provided to people taking part in a caravan to draw attention to the cases of missing Central American migrants in Mexico, the National Migration Institute, or INM, said.

The caravan is heading to Mexico City in two groups, with one leaving Guatemala City on July 24 and the other heading for the capital from Tenosique, a city in Mexico's Tabasco state, on July 26.

Temporary visas will be provided "to those who request them and have some type of documents to confirm their nationality," the INM said.

The visas will allow caravan members to "look for their missing relatives," the INM said.

The caravan, which includes citizens of Guatemala, Honduras, Nicaragua and El Salvador, "received an escort and assistance from officials of the INM's Beta Group for the Protection of Migrants, who provided water and medical assistance," the immigration agency said.

A group of migrants' rights activists met Monday at the Mexican Senate with lawmakers, officials and representatives of non-governmental organizations.

INM officials attending the meeting asked for assistance from migrants and their families in "reporting bad public servants with the goal of punishing them and preventing new abuses of authority," the immigration agency said.

Inter-American Commission on Human Rights rapporteur for migrant workers and their families Felipe Gonzalez wrapped up his visit to Mexico on Tuesday.

The rights official toured Mexico, meeting with representatives of non-governmental organizations, officials, migrants and migrants' relatives.

The meetings shed light on detentions, violence and sexual aggression against women, as well as numerous cases of extortion and people trafficking over the past 10 years, Gonzalez said.

Mexico should grant "temporary permits" to Central Americans passing through the country on their way to the United States to reduce attacks on them, Gonzalez said.

"Immediate action is needed to protect the lives of migrants," Gonzalez said, adding that "alternative mechanisms to detention" should be sought by Mexican officials.

The Inter-American Commission on Human Rights, or IACHR, is an organ of the Organization of American States.

The INM, however, pointed out that Mexico's new Migration Law "decriminalized irregular migration" and recognizes "that migrants have the right to access to justice, health care and education."

About 20,000 migrants are kidnapped each year in Mexico, with about $50 million in ransom paid to criminal organizations that often work with officials, Gonzalez said, citing information provided by activists.

At least 11,333 migrants, the majority of them from Central America, were kidnapped in Mexico between April and September 2010, the Mexican National Human Rights Commission, or CNDH, said in a report released in February.

Thousands of migrants, both Mexicans and foreigners, try to enter the United States each year via land routes from Mexico.

The trek is a dangerous one, with criminals and corrupt Mexican officials preying on the migrants.

Gangs kidnap, exploit and murder migrants, who are often targeted in extortion schemes, Mexican officials say.

An estimated 300,000 Central Americans undertake the dangerous journey across Mexico each year on their way to the United States.

Central American migrants follow a long route that takes them into Chiapas state, which is on the border with Guatemala, walking part of the way or riding aboard freight trains, buses and cargo trucks.

The flow of migrants has increased markedly in the northern and northeastern parts of Mexico since U.S. officials increased security along the border in the northwestern part of the country.