President Bashar al-Assad’s forces have surrounded rebels near the already war-damaged Crusader castle of Crac des Chevaliers, a UNESCO World Heritage site in central Syria, residents said on Wednesday.

Crac des Chevaliers suffered mortar hits last year when rebels from the town of al-Hosn below the hill-top castle hid behind its thick stone walls, built for battles hundreds of years ago. The violence had died down until this week.

Syria’s nearly three-year-old conflict has devastated whole city neighbourhoods and many ancient sites, including Aleppo’s medieval covered market and its Umayyad mosque. Looting has threatened tombs in the desert town of Palmyra and Roman temples have been damaged. […]