A Japanese journalist died of wounds sustained in Aleppo on Tuesday, the scene of heavy clashes between Syrian forces and rebels, a Syrian activist group said in a statement.
Japan's Kyodo news agency, quoting an official at the Japanese embassy in Turkey, identified the journalist as Mika Yamamoto, an award-winning reporter who worked for Tokyo-based independent news wire Japan Press.
Japan Press was not immediately available for comment. Its web site said Yamamoto, who was born in 1967, had covered conflicts in such places as Afghanistan and Iraq.
The Syrian Observatory for Human Rights said the Japanese reporter had been injured in the Suleimaniya district of Aleppo.
The Syrian activist group also said that a Lebanese journalist, a Turkish journalist and an Arab journalist, whose nationality it did not identify, had disappeared in Aleppo.
It was not possible to independently verify the account.
YouTube showed video that activists said was the Japanese journalist's body at a makeshift hospital.
In Tokyo, a foreign ministry official said the ministry was aware of the reports and its offices in the Middle East are looking into the matter.
Syrian President Bashar al-Assad, battling a 17-month-old uprising against his family's 42-year rule, has used fighter jets and helicopter gunships to pound rebel strongholds, often in cities. Insurgents in turn have stepped up their own attacks, hitting tanks, military convoys and security buildings.
At least 18,000 people have now been killed in Syria since the anti-Assad revolt began. At least 170,000 have fled the country, according to the United Nations, and 2.5 million need aid inside Syria.
(Reporting by Beirut and Tokyo newsrooms; Editing by Louise Ireland and Michael Perry)