* Draft deal extends Russian lease for 20-29 years
* Formal signing expected in October - sources
* Tajik base is Russia's largest foreign troop deployment
* Russia, Tajik leaders fret Islamist militancy may spread
By Roman Kozhevnikov
DUSHANBE, Sept 14 (Reuters) - Russia has negotiated a deal to extend its lease on a military base in Tajikistan for more than 20 years in exchange for discounted weaponry and training for the Central Asian state's armed forces, two sources close to the talks said on Friday.
The lease extension will end recriminations over a delayed deal to reinforce Russia's military presence on the southern fringes of the former Soviet Union before NATO troops begin withdrawing from next-door Afghanistan in 2014.
More than 6,000 Russian soldiers are stationed across three towns in Tajikistan, an impoverished former Soviet republic with an economy heavily reliant on money sent home by around 1 million migrant workers in Russia.
The 201st base is Russia's largest troop deployment abroad and is viewed by the Kremlin as a bulwark against the potential spillover of Islamist militancy into a region it still regards as its sphere of influence.
The current 10-year lease on the base is due to expire on Jan. 1, 2014.
A high-ranking source in Tajikistan's government, who took part in the negotiations, told Reuters that an extension of between 20 and 29 years had been agreed. A Russian diplomatic source said a period of 29 years had been agreed in principle.
"This could move a little, plus or minus five to seven years, but no more," the Russian source said. Both sources spoke on condition of anonymity because of the sensitivity of talks.
They said a formal agreement was expected to be signed in October by Russian President Vladimir Putin and Tajik President Imomali Rakhmon.
"The agreement has no financial aspect," the Tajik government source said. "In return (for extending the lease), Tajikistan will receive a discount on Russian arms and its officers will be trained in Russian military academies."
In power for two decades, Rakhmon was supported by Russian troops during a 1992-97 civil war. Tens of thousands died in fighting between the secular government and a loosely aligned opposition that included Islamist militants.
Wrangling over payment and the extent of Russia's influence in the strategic region had delayed a deal. Moscow had wanted to extend the lease for 49 years while Tajikistan's opening offer was 10 years, the Russian source said.
Rakhmon's government was always likely to extend Russia's lease, analysts said. As well as protection against the risk of Taliban-inspired militancy, a Russian troop presence is a lever for Tajikistan against its powerful regional neighbours.
Uzbekistan, with a population nearly four times the size of Tajikistan's, has periodically criticised its neighbour for pursuing hydroelectric projects that would dam rivers needed to irrigate Uzbek farmland downstream.
"Russia's military base serves as an umbrella protecting Tajikistan from the influence - or aggression - of other nations," said Dushanbe-based political analyst Jamshed Kadyrov.
"It would be suicidal to remain without at least the nominal protection of 'Big Brother'." (Writing by Robin Paxton; Editing by Andrew Osborn)