At least 18 soldiers were killed and 20 wounded on Thursday when an explosive device detonated on a military bus in the Damascus countryside, local outlet Sham FM said. It represents one of the deadliest attacks in months against Syrian government troops not on an active front line. Bus attacks in particular have been on the rise, including in the Damascus countryside. There was no immediate claim of responsibility for Thursday’s attack and no comment from Syrian authorities. The Syrian Observatory for Human Rights, a war monitor that counts casualties and covers military developments in the 11-year-old conflict, said that 17 soldiers were killed in the blast. A decade of conflict in Syria has killed hundreds of thousands of people and left the country fractured. Syrian government troops have managed to recapture much of the territory they had lost to opposition fighters. Security incidents have been on the rise around Damascus and other parts of Syria controlled by the government.