Washington/Mexico City - As US Secretary of State Hillary Rodham Clinton arrived Wednesday in Mexico for her first visit to the southern US neighbour, the US Congress raised alarm about growing drug violence south of the border.

Heightened concern about the inflow of illicit drugs into the United States and the backflow of money and arms into Mexico are sure to dominate Clinton's meeting with her Mexican counterpart Patricia Espinosa.

A growing standoff over free trade and the shortcomings of the North American Free Trade Agreement (NAFTA), which has failed to boost Mexico economically as much as had been expected since going into effect 15 years ago, were also on their agenda.

But the growing crisis situation in Juarez, the Mexican border city where 10,000 troops are maintaining martial law, has focussed most of the attention on the drug issue.

Mexico insists that the US must cut down the demand for illicit cocaine and other drugs to help solve its own problems as a largely transit country for drugs produced in Colombia and Peru.

Referring to the "ruthless" drug violence in Mexico, Senator Joe Lieberman, Democratic chairman of the Senate committee on homeland security, noted the irony that the mayor of Juarez must to live in El Paso, Texas, and commute to his offices by daylight for his own safety.

"The police chief (of Juarez) was forced to resign when drug cartels threatened to kill one of his officers every 48 hours unless he stepped down," Lieberman noted.

The lower US House of Representatives also held hearings Wednesday into Mexico's drug violence.

The US State Department over past weeks has warned US university students to skip their traditional spring break holidays in Mexico because of soaring murders. In 2008 alone, more than 6,000 murders were blamed on drug violence, including more than 500 police and security officers.

Clinton's visit comes a day after the announcement of a major US boost in its support of Mexican law enforcement and ramping up of border patrols, prompting The New York Times to carry a front page story under the headline: "Obama's Next Foreign Crisis Could Be Next Door."

Mexican President Felipe Calderon's aggressive crackdown on drug cartels over the past years, combined with an increased US security presence along the border, has resulted in a jump in violence in the region among trafficking gangs and retributions against police.

Juarez, with 1.5 million residents, saw 1,800 murders in 2008 blamed on drug conflicts and 390 killings so far this year. Gruesome beheadings in Juarez and elsewhere have become the order of the day. US President Barack Obama is to visit Mexico on April 16, on his way to the Americas summit in Trinidad on April 17-19. (dpa)