Images show aid trucks passing from Turkey into Syria through the Bab al-Hawa border crossing, the sole route through which UN assistance can enter the country's opposition-held northwest. In 2014, the UN Security Council allowed aid operations to cross at four points but last year -- after objections from Russia and China -- this was reduced to just Bab al-Hawa. The resolution on humanitarian aid access to Syria expires on July 10 and is up for a Security Council vote before then. STOCKSHOTS