Ukraine won't let the Russian aid convoy enter its territory, a senior aide to President Petro Poroshenko says.The 280 lorries will have to be unloaded at the border and the goods must be transported by vehicles of the International Committee of the Red Cross, Poroshenko's Deputy Chief of Staff Anatoliy Chaly says.Ukraine currently does not control all of its frontier with Russia. Some border posts are occupied by pro-Russian separatist forces.