A month has passed since a Japanese man was captured in northern Syria by the Islamic State militant group, but efforts to secure his release have so far produced few signs of progress.

Haruna Yukawa, 42, is believed to have been traveling with rebel fighters from the Islamic Front and the Free Syrian Army when he was captured on Aug. 14 by the Islamic State, during a firefight in Marea, roughly 30 km north of Aleppo. News outlets learned of his captivity three days later.

According to the Foreign Ministry, Japanese officials in Amman are doing their utmost to secure his release, including speaking to various groups with possible connections to his captors. But so far, there is little that can be disclosed, the officials said.

According to a source, a Japanese scholar in Islamic studies was asked to visit northern Syria earlier this month to provide translation to Yukawa's captors. But he was unable to meet Yukawa during his weeklong stay, the source said.