Assailants hurled an explosive device at a US consulate in a northern Mexico border city, damaging windows but causing no injuries, the consulate said on Saturday.
The device was thrown over a wall surrounding the consulate in Nuevo Laredo, across the border from Laredo, Texas, on Friday night. The consulate said in a statement it would be closed indefinitely.
It was the latest attack on US consulates and consulate staff in Mexico.
Suspected drug hitmen killed three people linked to the US consulate in Ciudad Juarez last month, provoking outrage from US president Barack Obama and putting new pressure on Mexico to stop growing violence. Gunmen also threw a grenade at the US consulate in Monterrey in 2008.
Drug violence is raging across Mexico and almost 20,000 people have died in the fight among cartels and with Mexican security forces since president Felipe Calderon launched his army-led crackdown on drug gangs in late 2006.
Nuevo Laredo and the surrounding state of Tamaulipas have seen a surge in drug-related violence since the start of the year as the Gulf cartel fights its former armed wing, the Zetas, for smuggling routes into the United States.
The violence is scaring off tourists and worries Washington, which is giving anti-drug aid, equipment and police training to Mexico. Some investors have frozen investment in factories in cities on the US border, especially in Ciudad Juarez, the most deadly spot in the drug war.
