NUEVO LAREDO, Mexico (AP) — Gunfire and burning vehicles in the Mexican border city of Nuevo Laredo led U.S. officials to close the U.S. consulate there and briefly shut down close border crossings Monday.

The gunfire erupted late Sunday after the arrest of a leader of one faction of the Northeast Cartel, the successor group to the old Zetas Cartel, Mexico's most bloodthirsty gang. Suspected cartel members opened fire and hijacked and burned vehicles, apparently in retaliation for the arrest.

U.S Customs and Border Protection said that southbound traffic from Laredo, Texas, into Nuevo Laredo at the Juarez-Lincoln and Gateway to the Americas bridges was suspended, but re-opened early Monday morning.

The U.S. consulate in Nuevo Laredo was closed to the public, and existing appointments were to be rescheduled. There were reports the consulate building was hit by gunfire, but the U.S. Embassy in Mexico City did not immediately confirm that.

U.S. Ambassador Ken Salazar said, "I have raised our grave concerns about these incidents and the safety and security of our employees directly with the government of Mexico."

The arrested suspected was not identified by his full name, in keeping with Mexican law.

The Mexican army said he was the leader of cartel gunmen known as "The Troops of Hell." They are an extremely violent and heavily-armed gang of hitmen.

The suspect's nickname — "The Egg" — corresponds to Juan Gerardo Treviño, a nephew of imprisoned Zetas leader Miguel Angel Treviño.

The suspect, who reportedly had two illegal guns when he was detained, faces charges of extortion, homicide and terrorism in Mexico. He also is wanted for extradition to the U.S. on charges of conspiracy to traffic drugs and launder money.