TOKYO — A female Japanese reporter has been killed after being caught in gunfire while covering clashes in Syria's northern city of Aleppo, the Japanese foreign ministry said Tuesday.

The Syrian Observatory for Human Rights said three other journalists were missing while covering the uprising against President Bashar al-Assad's regime

Japan's foreign ministry confirmed the dead reporter was Mika Yamamoto, 45, said an official in charge of Japanese nationals' safety abroad.

"She was at reporting work in Aleppo, northern Syria, when she was caught in gunfire," the official said.

Yamamoto had been working for the small Japan Press news agency and a colleague travelling with her identified the body, the official said.

She joined Japan Press in 1995 and had also covered the war in Afghanistan and the Iraq conflict, according to the company's website.

Japan Press has not issued a statement on her death.

The Britain-based Syrian Observatory for Human Rights had earlier said that a Japanese female reporter had died in Aleppo and that three other journalists were missing, including two Arabs -- one a Lebanese woman -- and a Turkish reporter.

"She was seriously wounded Monday while covering the clashes at Suleiman al-Halabi which have been going on since yesterday. We took her to hospital where she succumbed to her injuries," Rami Abdel Rahmane, the Observatory's president, told AFP, citing medical officials from the hospital.

"She was very likely hit by a projectile," added Rahmane, who was unable to give further details about the missing journalists.

A video posted by militants on YouTube showed a female body lying in a room. It was presented as the corpse of the Japanese journalist, and said she was killed by militia allied to Assad's troops.

A prominent injury could be seen on her right arm. Next to her, an Asian-looking man appeared to be asking for medical assistance.

AFP was unable to independently confirm the authenticity of the video, or the information presented in it.

Yamamoto was the fourth foreign reporter killed in the violence in Syria since March 2011.

French reporter Gilles Jacquier was killed on January 11 at central Syria's Homs, where American journalist Marie Colvin and French photographer both perished on February 22.