Senior US diplomat Linda Thomas-Greenfield will visit Turkey this week to push for the continuation of cross-border aid deliveries into war-torn Syria, before a UN Security Council debate that could end the humanitarian convoys. Ms Thomas-Greenfield will visit Turkey on Wednesday for talks with senior officials, humanitarians and Syrian refugees, the US mission to the UN said on Tuesday. The “visit comes as the United States works with the United Nations, allies and partners to reauthorise and expand the UN’s ability to provide humanitarian cross-border aid into Syria", the mission said. The mandate for the aid expires on July 10 and faces opposition from Russia, the Syrian government's main ally on the council. “Ambassador Thomas-Greenfield will emphasise the urgent need for additional crossings and stepped-up international assistance, as there is no viable alternative to alleviate the vast needs of vulnerable populations in northern Syria,” the US mission said. Those needs “have only been exacerbated by the Covid-19 pandemic”. The US mission said the trip would “recognise Turkey’s crucial role in the facilitation of cross-border assistance” and the work of humanitarians in providing “life-saving assistance to millions in Syria who otherwise have no access to desperately needed food and supplies". The 15-nation UN council originally authorised cross-border aid operations into Syria in 2014 at four points. Last year, it reduced access to one entry from Turkey after opposition from Russia and China to renewing all four. The US and other council members have pushed to expand cross-border operations. A resolution to extend council approval needs nine votes in favour and no veto from any of the five permanent members – Russia, China, Britain, France and the US. The UN's top humanitarian, Mark Lowcock, has called cross-border aid deliveries a “lifeline” for about 3 million Syrians in the country’s turbulent north, where rebels continue to hold out against forces loyal to President Bashar Al Assad. Russia says the deliveries are no longer necessary and that distribution of food, fuel, medicine and other aid should be overseen from the capital, Damascus.