The motive for Mr Surabaldiyev's killing is not clear

It was not clear who killed Jyrgalbek Surabaldiyev, or why he was targeted, police said.

There have been a number of security breaches in Kyrgyzstan since former President Askar Akayev was ousted from power during popular protests in March.

Fresh presidential elections are due to be held in the Central Asian nation next month.

Eyewitnesses say Surabaldiyev was gunned down by two unidentified men in broad daylight in Bishkek's central square. The parliamentary deputy died on the spot and the two men then escaped from the scene by car.

The Kyrgyz authorities are investigating the incident, which they say appears to have been a contract killing.

Occasional contract killings in Kyrgyzstan are sometimes the result of business rivalries, but Kyrgyz officials say the motive on this occasion may also have been political.

The BBC's correspondent in the region, Ian MacWilliam, says business and politics are in any case closely linked in Kyrgyzstan, where the former president's inner circle was thought to control large parts of the country's economy.

The shooting follows an attack on MP Bayaman Erkinbayev in April

Some of Surabaldiyev's opponents accused him of organising groups of young men who attacked anti-Akayev protestors who eventually drove the former president from power.

Some also say he helped organise the massive looting which followed Mr Akayev's overthrow.

This shooting is just the latest sign of continuing political tensions in Kyrgyzstan as the interim government prepares for new presidential elections a month from now.

One presidential candidate, Bayaman Erkinbayev, said in April that he had escaped an attempt on his life.

He was shot and wounded in the face in Bishkek, although police said the motivation for the attack may not have been political. Like Surabaldiyev, Mr Erkinbayev had prominent business interests.

In recent months many protests of one sort or another have been organised by groups with political or economic complaints which they say the interim government is not addressing, our correspondent says.