(Adds details of third bomb scare, quotes, byline)
By Julian Cardona
CIUDAD JUAREZ, Mexico, Feb 25 Mexico closed an international airport in a northern border city at the heart of the country's drug war on Wednesday after a bomb scare during a visit by government officials, the army said.
An army spokesman said there were other bomb threats at the international bridge between Ciudad Juarez and El Paso, Texas, and at a federal government building in the city, during an official visit by Interior Minister Fernando Gomez Mont and other officials attending a security meeting.
The spokesman said traces of explosive were found in a vehicle parked at Ciudad Juarez airport, which was evacuated by soldiers and federal police but reopened by late afternoon.
"Anonymous calls to the police and army alerted us to the threats, but they turned out to be false," army spokesman Enrique Torres said.
Frightened travelers waited outside the airport and flights were diverted to the state capital, Chihuahua.
Gomez Mont is expected to announce new troop reinforcements for Ciudad Juarez and Chihuahua state, which has seen the worst violence from turf wars sparked by Mexico's two-year-old army crackdown on drug cartels.
President Felipe Calderon has sent about 45,000 troops across the country, but clashes between rival gangs and security forces killed some 6,000 people last year.
Even with about 3,000 troops and federal police in Chihuahua state, more than 250 people have died in drug violence this month in Ciudad Juarez -- around 10 a day -- in a sharp escalation of unprecedented violence.
Drug trade experts say Mexico's most-wanted man, Joaquin "Shorty" Guzman, who leads a cartel from the Pacific state of Sinaloa, is vying to take Ciudad Juarez's lucrative smuggling route from local cartel leader Vicente Carrillo Fuentes.
Law and order in the city has collapsed as Guzman's hitmen seek to eliminate the Juarez cartel's drug smuggling structure. (Additional reporting by Robin Emmott in Monterrey)