Reuters, Switzerland :The United Nations hopes that political talks between the warring sides in Syria will clinch local ceasefires to allow vital food and medicines to reach millions of civilians, the UN humanitarian chief said on Thursday.Valerie Amos, in an interview with Reuters a day after an international conference on Syria, said mediator Lakhdar Brahimi would press the government and opposition on these humanitarian issues at meetings due to start later in the day.The two sides, meeting for the first time, vented their mutual hostility on Wednesday but Brahimi said the enemies may be ready to discuss prisoner swaps, local ceasefires and humanitarian aid.”I have discussed this with Mr. Brahimi and he’ll continue to push this. Because political negotiations can take a very long time. And as we saw yesterday, there are big differences between the parties,” Amos said in an interview in Montreux, Switzerland. “But if we are able to get a major push on getting into these communities, it would make a significant difference.”She said it was crucial to gain access to some 250,000 people trapped in besieged communities, many of them in Aleppo, Homs and near Damascus, who have been out of reach for many months. Some say they have been reduced to eating grass in order to avoid starvation.Another 2.5 million people are in “hard-to-reach” areas, having received UN relief supplies just once or so, Amos said. “The key issue for us is that control of communities shifts all the time. We want to really take advantage when there is a sense we can move very quickly to try to do that,” she said, adding that she had met with an opposition delegate in Montreux.