US Vice President Kamala Harris and Mexico's President Andres Manuel Lopez Obrador pledged Friday to cooperate on resolving the roots of the long-running and politically sensitive issue of illegal migration into the United States.

Harris, speaking with Lopez Obrador in a virtual meeting, said they should work together on helping El Salvador, Guatemala and Honduras improve conditions and persuade many migrants to stay home.

"It is in our countries' mutual interest to provide immediate relief to the Northern Triangle and to address the root causes of migration," Harris said.

"Most people don't want to leave home and when they do it is often because they are fleeing some harm or they are forced to leave because there are no opportunity."

Harris said that it was in the "mutual interest" of the United States and Mexico to address the "root causes" of mass emigration from the three Northern Triangle nations.

US Vice President Kamala Harris will be visiting Mexico in June US Vice President Kamala Harris will be visiting Mexico in June Photo: AFP / MANDEL NGAN

"Our approach is to work with international institutions, to work with nations worldwide, the private sector and community organizations... and build a sense of hope for the people of the Northern Triangle," she said.

Lopez Obrador referred to the history of US-Mexican tensions over migration and said "we need to understand one another and avoid fighting."

"We are in agreement when it comes to the policies that you are undertaking when it comes to migration and we will help. That is what I can say as of now. You can count on us."

President Joe Biden tapped Harris in March to coordinate an overall response to the surge in undocumented migrants and asylum seekers at overwhelmed US border facilities.

She is due to travel to Mexico and Guatemala in June for her first foreign trip as vice president.