India's indigenously developed nuclear capable Prithvi-II ballistic missile failed to take off during a user trial from the Integrated Test Range at Chandipur off the Orissa coast on Friday apparently due to a technical problem, defence sources said. Though the ITR authorities were not immediately available for comment, defence sources said the sophisticated missile could not take off during the planned trial from the launch complex-III of the test range due to some "technical snag." "The failure to lift Prithvi-II was due to a snag either in the main missile or the sub-system, including the launcher," they said, adding the test-fire was slated to be held as part of user's trial by the armed forces.During today's planned trial, a noise could be heard as smoke billowed from the launch site around the time of the blasting. Efforts were on to ascertain the exact reason behind the failure on the part of the missile to take off and defence scientists were examining the matter thoroughly, they said. The last four user's trials of the surface-to-surface missile were successfully conducted during the about one year period, from the same site in the ITR. The last trial was conducted on June 18, this year. The test firing of the state-of-the-art missile, which has already been inducted into armed forces, was planned as users trial by the specially formed "Strategic Force Command" (SFC), the sources said.