UPDATE 1-Clinton optimistic on signing India defence pact

(Adds details, byline)

By Arshad Mohammed

MUMBAI, July 18 (Reuters) - U.S. Secretary of State Hillary Clinton on Saturday said she expected to finalise a defence agreement essential to allowing U.S. companies to sell sophisticated arms to India.

"We are working very hard to finalise a number of agreements. I am optimistic that we will get such agreements resolved and announced," Clinton told reporters in Mumbai in response to a question about an arms "end-user monitoring" pact.

Under U.S. law, such a pact is necessary for U.S. firms to bid on India's plan to buy 126 multi-role fighters, which would be one of the largest arms deals in the world and could be a boon to Lockheed Martin Corp (LMT.N) and Boeing Co (BA.N).

That deal is worth an estimated $10.4 billion, part of India's $30 billion plan to modernise its military over the next five years.

Lockheed and Boeing are competing with Russia's MiG-35, France's Dassault Rafale, Sweden's Saab (SAABb.ST) KAS-39 Gripen and the Eurofighter Typhoon, made by a consortium of British, German, Italian and Spanish firms (EAD.PA) (SIFI.MI) (BAES.L), for the contract.

Clinton is also expected to work on finalising agreements around a civilian nuclear pact signed last year, and U.S. officials hope she will announce two sites where U.S. firms would have the exclusive right to build nuclear power plants.

The State Department has estimated that could be worth up to $10 billion for U.S. companies. The two major U.S. nuclear reactor builders are General Electric Co. (GE.N) and Westinghouse Electric Co, a subsidiary of Toshiba Corp (6502.T). (Writing by Bryson Hull; Editing by Alex Richardson)