CIUDAD JUAREZ, Mexico – The U.S. State Department said Friday it is evaluating threats surrounding the consulate in the Mexican border city of Ciudad Juarez as hundreds of people with appointments for visa applications and other services stood outside the shuttered office wondering what to do.

U.S. officials gave no details on the threats that prompted an indefinite closure. The consulate is the only place that processes immigrant visas in Mexico.

“It is a very significant facility for us,” State Department spokesman P.J. Crowley said. “There is some threat information that we received that we are evaluating. It is hard to know or judge whether the threat is related to the broad area where the consulate is or to the consulate itself.”

Even as the State Department increases protection for employees and their families from the intensifying violence on the Mexican border, closing the Juarez consulate is the most drastic step to date — coming four months after drug gangs killed three people connected with the office.

Maria Concepcion Morales traveled with two children 16 hours by bus from Zacatecas to be on time for her 7:45 a.m. appointment for a tourist visa.

“What am I going to do?” she said. “I don’t have enough money to stay until Monday, when they’re saying they will reopen.”

Many complained of the lack of support for those stranded by the sudden closure.

“I told them I was outside and they said they had no information and hung up. What kind of help is that?” said Martha Lara Munos, who came from the central state of Morelos with two children and her mother to apply for a resident visa.

The U.S. Embassy said it would reschedule appointments for visa applications through its call center, and provided a number that U.S. citizens could call for passport appointment and other services.

A turf battle between the Juarez and Sinaloa drug cartels has made Ciudad Juarez one of the world’s most dangerous cities. More than 4,000 people have been killed in the city of 1.3 million since the beginning of 2009.