MEXICO CITY The U.S.-Mexican border reminds people in some parts of the world of the Berlin Wall. On the beach separating Tijuana to the south and San Diego to the north is a more than 3-meter-high steel fence that extends far into the ocean.

As it heads out of the city and east into the desert, the steel gives way to concrete but remains a wall to prevent Mexican citizens from crossing illegally into the United States. Those who manage to scramble over the barrier face pursuit by the U.S. border patrol.

But if Mexican President Vicente Fox has his way, the border between the dissimilar neighbors would resemble today's European Union rather than the Iron Curtain.

His idea to convert the three-country North American free trade agreement into a continent-wide common market mirroring Europe has not been well-received in Washington. Although the United States does not appear ready for such a change, the countries' longtime dispute over illegal immigration has been diminishing recently.

U.S. President George W. Bush, who has established a quick friendship with Fox, is considering granting temporary guest worker status to the 3 million undocumented Mexican immigrants in the United States, DPA quoted the White House as saying Monday. This news came after the United States obligated itself in a June action plan to stop using guns against border crossers.

On the other side of the line, Mexican officials are trying to talk their countrymen out of leaving their homeland. Since the beginning of July, the government has run television spots warning potential immigrants of the dangers of crossing the border, particularly in the Desert Summer.

However, the number of Mexicans and U.S. citizens of Mexican origin living in the United States has risen by more than 50 per cent in the 1990s to 20.6 million. That 7.3 per cent of the entire U.S. population sends about 6 billion dollars to relatives back home annually and accounts for one of Mexico's most valuable currency sources as well as life-saving income for many poor, rural villages in provincial Mexico.

Like none of his predecessors, Fox has reached out to his countrymen in the United States. On Tuesday, he finished a five-day tour of the U.S. Midwest, speaking to emigrants while calling for the legalization of undocumented Mexican workers in the country and protection of border crossers -- at least 300 of whom died last year of exposure or dehydration in the desert.

Fox's government sees these expatriates not only as a prime source of foreign currency but also as a lobby for Mexico's political aims at a time when Bush is seeking to gain Mexican Americans' support at the voting booth.

The run to the U.S.-Mexican border has brought other economic benefits to both the United States and Mexico. The desert that the two countries share is now blooming with new factories and homes.

The population in the border area has risen 30 per cent in the past 10 years. Low-wage factories have sprung up along the south side of the border in which millions of Mexicans make electrical appliances and textiles for export to the United States. And English and Spanish, tacos and hamburgers, nortena and rock music exist side by side there in the give-and-take mixed culture.

In other areas, it has created a culture clash. The immigration influx has brought Spanish speakers to previously isolated communities as far as Main in the U.S. Northeast, creating cultural tension and major demographic shifts across the country.

The population of most border cities, for instance, is majority Hispanic, creating unease and a fear among some native English speakers of a foreign invasion.

But even if Fox does achieve all his political goals, including the legalization of undocumented immigrants, experts said Mexico's long-term economic growth of 7 per cent a year should dry up the immigrant flow.