The Popular Front for the Liberation of Palestine militant group said five of its members were killed Wednesday and 10 others wounded in a blast near the Lebanon-Syria border.
The group said the blast happened in the town of Qusaya and blamed it on an Israeli airstrike.
Reuters quoted an Israeli official as saying Israel's military was not involved.
The PFLP has conducted numerous attacks against Israel during the past 50 years, including hijacking and bombing airliners.
The United States has designated the group as a foreign terrorist organization.
Some information for this report came from The Associated Press and Reuters.