* Pakistani, Afghan leaders in Tajikistan
* Regional powers concerned with instability
* Tajik forces kill key militant in shootout
DUSHANBE, July 29 (Reuters) - Tajikistan's leader urged visiting Pakistani President Asif Ali Zardari on Wednesday to work more closely together to prevent the rise of instability in Central Asia, a vast former Soviet region north of Afghanistan.
Zardari and Afghan President Hamid Karzai were both in the Tajik capital Dushanbe on the eve of a regional security summit also due to be attended by Russian President Dmitry Medvedev.
Regional powers are concerned that intense fighting in Afghanistan as well as Pakistan's attacks on Taliban strongholds may disturb a fragile peace in nearby Central Asia.
Addressing Zardari, Tajik President Imomali Rakhmon said more needed to be done to maintain stability in the region.
"The two sides have also emphasised principal positions on fighting against terrorism and extremism," Rakhmon told reporters after talks with Zardari.
"We do share similar and close positions on these issues and our countries should have taken coordinated actions aimed against this antagonistic phenomenon," he added, without elaborating.
Speaking alongside Rakhmon at the presidential palace in Dushanbe, Zardari avoided specifics.
"We will stand together against the challenges of this century," he said. "... we are looking forward to strengthen our cooperation".
Fears about stability have been reinforced in recent months as troops in Tajikistan, Kyrgyzstan and Uzbekistan engaged in a string of shootouts across the region with gangs identified by the authorities as Islamist rebels. [ID:LT472379].
As Zardari and Rakhmon spoke, a Tajik source told Reuters state forces had shot dead a suspected Islamist rebel accused by the authorities of spearheading an armed insurgency on the country's border with Afghanistan. [ID:nLT461255]
Karzai was due to meet Rakhmon later in the day.
The trend in Central Asia is of particular worry to the United States which uses the region as a key transit point for supplies headed for its troops fighting in Afghanistan.
(Writing by Maria Golovnina; Editing by Sonya Hepinstall)
For a feature on the Islamist movement in the region, please click on [ID:nLR230840]
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