Get breaking news alerts and special reports. The news and stories that matter, delivered weekday mornings.

Agents at a U.S. military post in Texas are searching for a soldier who has been missing for three days.

Private First Class Vanessa Guillen, 20, was last seen Wednesday afternoon in a parking lot at Fort Hood, where she's stationed, wearing a black T-shirt.

Vanessa Guillen. United States Army

"Her car keys, barracks room key, identification card and wallet were later found in the armory room where she was working earlier in the day," officials said in a press release.

Let our news meet your inbox. The news and stories that matters, delivered weekday mornings. This site is protected by recaptcha

Friends and family of Guillen have flooded their social media accounts with pleas to the public to contact the authorities if anyone has any information.

Mayra Guillen wrote on a Facebook post that her sister's phone was last tracked on Belton, Texas, about 20 minutes away from where she was last seen. Neither her boyfriend or relatives have heard from her since she disappeared, she said.

"Please help me find my girlfriend," Guillen's boyfriend, Juan Cruz, tweeted on Friday. "Please anything helps."

Please help me find my girlfriend her name is Vanessa guillen

Height 5'3

She has 3 tattoos on her left arm

Please anything helps. pic.twitter.com/GZLBkamc4h — quan (@trapixxx) April 24, 2020

"An extensive search is underway by military members, as well as civilian and military police," authorities said. Special agents from the U.S. Army Criminal Investigation Command are also involved in the search.

Fort Hood Military Police also issued a "be on the lookout" notice to alert surrounding law enforcement agencies to Guillen's disappearance.

Guillen is of Hispanic descent, 5 feet, 2 inches tall, and weighs 126 pounds with black hair and brown eyes.