India's indigenously developed nuclear capable Prithvi-II ballistic missile failed to take off during a user trial today. The missile was tested at the Integrated Test Range at Chandipur off the Orissa coast. According to Defence sources in Balasore, the failure to lift was due to a snag either in the main missile or the sub-system, including the launcher. A top Defence scientist Dr Prahlada said the missile is already a proven one and there should be no doubts about its reliability.