Syria's differences with the United Nations and Lebanon topped the agenda when Syrian President Bashar Assad held talks with Egyptian President Hosni Mubarak here Tuesday, Egypt's foreign minister said. Assad flew to Cairo for a visit of only a few hours and immediately went into talks with Mubarak. Syria has come under increasing international pressure since the UN investigation into a Lebanese leader's assassination in February has accused its government of failing to provide full cooperation. After their talks, neither Assad nor Mubarak spoke to the media, Egyptian Foreign Minister Ahmed Aboul Gheit said they "focused on the main regional issues related to the Mehlis investigation and the latest UN Security Council decision and how Syria dealt with it, as well as Syrian-Lebanese relations and how to advance them." Last week, the UN Security Council extended the mandate of the investigation by six months. Syria has pledged to cooperate and denied that it hasn't offered full assistance so far. Egypt, the political heavyweight of the Arab world, has been trying to mediate between Syria and the West.