She has tended to the poorest of the world's poor, dispensing food and medicine in the slums of India, Africa and Asia. Now Mother Teresa is opening her newest mission on a doorstep of the United States.

The 1979 Nobel Peace Prize winner has chosen Tijuana, Mexico, a border town popular with American tourists, as the site of her 400th Missionaries of Charity center for the poor.Dedicated Friday in a ceremony attended by former California Gov. Jerry Brown, the mission was founded close to Tijuana's central bus depot, where thousands of Latin American migrants arrive each day, some fleeing war, most searching for jobs.

These "bus people," as they are called, will now be Mother Teresa's charges.

"Any man, woman or child that nobody wants, let them come to the sisters. We want them," the 77-year-old nun told reporters.

And as she has in nearly 80 other countries, Mother Teresa refused to concern herself with the economic and political forces that leave people destitute.

"I never get mixed up with politics," the Albanian native said while fingering her rosary beads.

Asked if her presence in Tijuana might prompt Americans to offer more aid to their poorer southern neighbors, she demurred.

"I never think like that," she said, then added, "Once we have the shelter for the homeless, then we will create more knowledge of these people."

The homeless shelter will be part of a 12-acre Missionaries of Charity compound. When finished, the center also will house terminally ill people and unwed mothers, a special concern for Mother Teresa, who last month in San Diego called abortion "the greatest destroyer of peace."

The Tijuana mission will serve as the headquarters for 30 Missionaries of Charity priests, who have relocated from as far away as New York to work with Mexico's poor.

Mother Teresa first considered opening the mission at the request of Bishop Emilio Berlie during a visit to Tijuana last year, said Dr. Anita Figueredo, the nun's long-time associate.

When she began scouting around, Figueredo recalled, "all she wanted was a place to distribute food. But when she saw (the bus depot), she said, "We should have more, we should have a refuge."

With land donated by the city of Tijuana and Berlie's diocese, Mother Teresa characteristically started cutting through red tape on both sides of the border to get needed supplies.

"She goes right to the top," said Figueredo.

"She's hit up all my friends," said Brown, who spent three weeks with Mother Teresa in Calcutta this year and came to Tijuana at her invitation.

As the rest of the city filled up with Americans anxious to party through the July Fourth weekend, Mother Teresa quietly received flowers and embraces from Mexican Catholics, many of whom have signed up to work at her mission.