More than 6,000 people were killed trying to cross the US-Mexican border illegally in the past 15 years, the American Civil Liberties Union said Wednesday.

The ACLU urged the North American neighbors to declare a humanitarian crisis in the area, protect human lives and change policies that have led to an increase in the number of people who die trying to make the illegal move.

"The current policies in place on both sides of the US-Mexico border have created a humanitarian crisis that has led to the deaths of more than 5,000 people," said Kevin Keenan, Executive Director of the ACLU of San Diego.

"Because of deadly practices and policies like Operation Gatekeeper, the death toll continues to rise unabated despite the decrease in unauthorized crossings due to economic factors," he added.

The ACLU data were from the Mexican foreign ministry. It says 6,607 people died trying to cross the border since 1994. US Homeland Security officials have put the figure at 3,861.

Under Operation Gatekeeper, launched 15 years ago by the United States, security was greatly stepped up at crossings in urban areas, which ended up sending undocumented migrants to remote areas trying to reach the United States.

"Instead of policies that foster fatalities, we need sensible, humane immigration and border policies that prioritize human life over death," argued Andrea Guerrero, Field and Policy Director of the ACLU of San Diego.