KABUL (Reuters) - The United Nations envoy for Afghanistan has arrived in Kabul for talks with the ruling Taleban amid preparations by the Islamic movement for an offensive against their last major foe. Lakhdar Brahimi is expected to hold several days of talks with the Taleban, who control 90 percent of the country, in an effort to persuade its leadership to give peace talks another chance, diplomatic sources said. Brahimi arrived from Tashkent where inconclusive talks between the Taleban and an opposition alliance were held at a meeting of the so-called Six Plus Two group of Afghanistan‘s neighbouring states plus U.S. and Russian officials. In Tashkent Brahimi was sombre about prospects of heading off a summer offensive by the Taleban to dislodge Ahmad Shah Masood, its last powerful enemy, from his bastion in the east of the country or from front lines just north of Kabul. Reinforced by hundreds of Islamic militants from Pakistan and some from Arab countries, the Taleban are preparing to launch what has become a traditional summer offensive in a country which has known 20 years of guerrilla war. The Tashkent meeting ended with both the Taleban and opposition representatives saying they would consult their leaders before deciding on the next move. But there appeared to be no change from entrenched positions, with the Taleban effectively asking Masood to stop fighting and join its government, the sources said. Brahimi‘s task is to get Taleban agreement to form a broad-based government grouping all ethnic and political factions but the Taleban say their control of most of the country and the defection of ethnic leaders gives them that title. Masood‘s umbrella alliance includes representatives of ethnic groups outside the Taleban‘s Pashtun base, the largest such grouping in the country. The Taleban want world recognition as the government of Afghanistan but are denied it by all but Pakistan, Saudi Arabia and the United Arab Emirates. The U.N. recognises the government of Berhanuddin Rabbani, whom the Taleban ousted three years ago, and which has the powerful support of Iran.