The United States is closing temporarily its consulate in this lawless Mexican border city after rival drug gangs clashed with bazookas, hand grenades and heavy machine-gun fire. "A violent battle involving unusually advanced weaponry took place between armed criminal factions last night in Nuevo Laredo," U.S. Ambassador to Mexico Tony Garza said on Friday. He said he was ordering the consulate in Nuevo Laredo closed for all of next week and would only reopen it if the security situation improved. Garza called on Mexico to swiftly bring the situation under control, Reuters reported.