UPDATE 1-Medvedev raps Russia shipmaker over late India deal

* Medvedev lambasts shipbuilder for late delivery to India

* Sevmash cites higher costs, technology problems

* Medvedev says Russia must modernise its navy by 2020

(Adds Medvedev quotes)

By Denis Dyomkin

SEVERODVINSK, Russia, July 2 (Reuters) - President Dmitry Medvedev on Thursday lashed out at Russian shipbuilder Sevmash for delays on a landmark contract with India, traditionally a close trading partner.

Arms exports, which exceeded $8 billion last year, are a key source of revenue for Russia. India and China account for the bulk of Russia's defence industry sales.

In a $1.6 billion deal signed in 2004, Russia was to modernise the Admiral Gorshkov at Sevmash, in the northern port of Severodvinsk, and deliver the aircraft carrier by 2008.