Awwal 25, 1432 / April 29, 2011, SPA -- UN Secretary General Ban Ki-moon called Friday for Nepalese parties to overcome their deep differences and agree on a new constitution by a May 28 deadline, according to dpa. "The secretary general urges all parties in Nepal to exert the utmost effort in reaching consensus on outstanding issues, including the integration and rehabilitation of Maoist army personnel and fundamental issues regarding the new constitution," UN spokesman Martin Nesirky said. The peace process involving the ruling party and communist parties had produced "significant achievements ... but remains overdue and incomplete due to continuing differences among the parties," Nesirky said. The UN mission in Nepal withdrew from the country in mid-January amid the political deadlock on issues of demobilization and reintegration of former Maoist combatants into society. The political differences have so far prevented the completion of drafting a new constitution in the Constituent Assembly.