Drama on the U.S.-Mexico border

An undocumented immigrant is detained by the U.S. Border Patrol near the U.S.-Mexico border near Mission, Texas.

A group of 16 immigrants from Mexico and El Salvador said they crossed the Rio Grande River from Mexico into Texas during the morning hours before they were caught. The Rio Grande Valley sector of has seen more than a 50 percent increase in illegal crossings from last year, according to the Border Patrol.

Agents say they have also seen an additional surge in immigrant traffic since immigration reform negotiations began this year in Washington D.C. Proposed refoms could provide a path to citizenship for many of the estimated 11 million undocumented workers living in the United States.

All photos from April 11, 2013

A U.S. Border Patrol canine team works with an U.S. Air and Marine agent to detain an undocumented immigrant after chasing him down near the U.S.-Mexico border.

An undocumented immigrant from El Salvador looks on after being detained by the U.S. Border Patrol near the U.S.-Mexico border.

U.S. Border Patrol agents detain undocumented immigrants near the U.S.-Mexico border.

A U.S. Air and Marine helicopter assists U.S. Border Patrol agents in finding undocumented immigrants near the U.S.-Mexico border.

The Rio Grande River forms the border between the United States (L), and Mexico in Hidalgo, Texas.

Undocumented immigrants from El Salvador sit handcuffed after being detained by the U.S. Border Patrol near the U.S.-Mexico border.

Border Patrol agents detain undocumented immigrants near the U.S.-Mexico border.

A U.S. Border Patrol canine team stands nearby after helping detain a group of undocumented immigrants near the U.S.-Mexico border.

U.S. Border Patrol and U.S. Air and Marine agents work together to detain an undocumented immigrant after chasing him down near the U.S.-Mexico border.

U.S. Border Patrol agents detain undocumented immigrants near the U.S.-Mexico border.

U.S. Border Patrol and U.S. Air and Marine agents detain an undocumented immigrant after chasing him down near the U.S.-Mexico border.

A U.S. Air and Marine helicopter searches for undocumented immigrants in thick brush near the U.S.-Mexico border.

A U.S. Border Patrol canine team stands nearby after they helped detain a group of undocumented immigrants near the U.S.-Mexico border.

A U.S. Office of Air and Marine (OAM) agent (L) and a U.S. Border Patrol agent talk while on patrols near the U.S.-Mexico border.

U.S. Border Patrol agents have an undocumented immigrant remove a second pair of pants after detaining him near the U.S.-Mexico border.

A marker over the Rio Grande River notes the border between the United States and Mexico.

U.S. Office of Air and Marine (OAM), pilot Rob Smith performs a pre-flight check on an Astar B-2 helicopter before flying a patrol along the U.S.-Mexico border.

An agent from the U.S. Office of Air and Marine stands near the U.S.-Mexico border.

A U.S. Office of Air and Marine (OAM), helicopter is brought out of a hangar before flying a patrol along the U.S.-Mexico border.