ANCHORAGE, Alaska (AP) — Ten FBI agents are traveling to a northwestern Alaska town to assist in a search for a 10-year-old girl, officials said.

Ashley Johnson-Barr was last seen at a playground in Kotzebue's Rainbow Park at about 5:30 p.m. Thursday, the Anchorage Daily News reported Monday. Her family reported her missing when she did not return home that evening.

Kotzebue police, volunteers and other groups have conducted searches since her disappearance. Her cellphone was found in the street about half a mile (0.8 kilometers) from the park, Kotzebue Police Chief Thomas Milliette said in a statement.

Alaska State Troopers are leading the investigation and requested assistance from the FBI, trooper spokesman Jonathan Taylor said.

"It's still a search-and-rescue operation at this point," Taylor said.

FBI spokeswoman Staci Feger-Pellessier said 10 agents were scheduled to arrive in the town Tuesday.

Other state and federal agencies have assisted in search efforts. A U.S. Coast Guard helicopter conducted a fly-by of coastal areas, and aircraft from Alaska Wildlife Troopers have also been used.

The Alaska Incident Management Team, a statewide emergency response group, is also supporting the search.

"We are investigating the incident and exploring all possibilities," Taylor said, when asked if officials have found evidence indicating foul play.

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Information from: Anchorage Daily News, http://www.adn.com