The broad strategy, outlined in 20 pages, is geared toward addressing the root causes of migration from Central America and dealing with corruption in the region.

Since March, Harris has been leading the Biden administration’s efforts to address the causes of migration from El Salvador, Guatemala and Honduras. In her plan, Harris wrote that “we will build on what works.”

“It will not be easy, and progress will not be instantaneous, but we are committed to getting it right,” Harris said. She also emphasized that the U.S. “cannot do this work alone” and that the governments of Mexico, Japan and Korea, as well as the U.N., have pledged to join the U.S. “in providing relief to the region.”

“The strength and security of the United States depends on the implementation of strategies like this one,” Harris wrote.

For more reporting from the Associated Press, see below:

Harris said that efforts to address root causes of migration from the three Central American countries won’t produce immediate results as she unveiled her strategy, which expands on principles the Biden administration previously outlined.

Harris said deep-seated motives for people to leave Guatemala, Honduras and El Salvador include corruption, violence and poverty.

The plan, which avoids deadlines, supports short-term relief for migration pressures like extreme weather while committing sustained attention to long-term motivations for people to leave their countries.

Harris noted that she recently traveled to Guatemala, “where one of the largest challenges is corruption.” On Tuesday, the Biden administration said it suspended cooperation with Guatemala’s attorney general’s office after the firing of the agency’s top anti-corruption prosecutor, saying it “lost confidence” in the country’s willingness to fight corruption.

The White House also released a “Collaborative Migration Management Strategy,” which Biden ordered in February to outline how the United States will work with other countries to address migration flows. The 14-page document summarizes earlier announcements and espouses goals that Biden and top aides have outlined before. They include expanding protections and job opportunities in countries where people are leaving, creating more legal pathways to come to the United States and fostering “secure and humane management of borders.”

Harris’ task, which Biden assumed when he was President Barack Obama’s vice president, is enormous in scope and complexity, and the administration has struggled for short- and long-term responses.

U.S. border authorities reported large numbers of arrivals at the Mexican border in June, with significant increases in people arriving in families and children traveling alone. The trend appears to be continuing in July, when soaring temperatures often deter people from coming.

A group of 509 migrants from Central and South America turned themselves in Monday night in Hidalgo, Texas, hours after another group of 336 migrants was encountered nearby, said Brian Hastings, the Border Patrol sector chief in Rio Grande Valley, the busiest corridor for illegal crossings.

On Monday, the Department of Homeland Security said it resumed fast-track deportations, known as expedited removals, for “certain” families that don’t express fear of being returned home. While it never announced a suspension, many families that enter the country illegally have been getting released in the United States with orders to appear in immigration court or report to immigration authorities.