The article does not say that US has assisted India in developing ABM. But it has the father of Indian missile defence indicating that US assistance is needed. If US assist India, it would be covert and not announced. This is highly likely. This article is from 2008.
India: Missile defense dreams / ISN
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While Israel and France have provided India with technical support, some experts remain skeptical. Stratfor analyst Nathan Hughes told ISN Security Watch that ballistic missile defense was not something that the agency could just pick up.
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haven't seen evidence suggesting that the DRDO is either capable of that level of technological sophistication or has pursued a representative test and evaluation program anywhere close to sufficient to field a meaningful BMD [ballistic missile defense] capability."
"Even the US has yet to succeed in having a fool-proof shield in place when it has been working concertedly on this […] for the last three decades with over US$100 billion invested in a wide range of technologies," Hughes argued.
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India's indigenous defense programs do not have a good track record, with many ambitious projects either stalled or delayed. Saraswat, the father of India's interceptor missile program, while expressing confidence in recent development work, has indicated that US support is needed.
Lockheed Martin, which pioneered the Patriot and THAAD (Terminal High Altitude Area Defense) anti-missile system, is considering collaboration with the DRDO on BMD development. In early February, Lockheed's Richard Kirkland hinted that "exploratory discussions" had taken place with Indian government and industry representatives on future ABM collaboration.