BEIJING (AFP) - China's President Xi Jinping headed to Central Asia on Tuesday ahead of a G-20 summit, state-run media reported, in visits expected to see energy deals and talks on slowing growth.

Mr Xi will start in Turkmenistan before meeting Group of 20 world leaders in St Petersburg on Thursday, then stop by Kazakhstan, Uzbekistan and Kyrgyzstan, the official Xinhua news agency and China Daily newspaper said.

The central Asian countries were once all part of the Soviet Union, but China - which has huge demand for energy - is increasingly influential in the area.

In Central Asia, Mr Xi is set to sign agreements on oil, natural gas, transport and investment, the China Daily cited vice-minister of foreign affairs Cheng Guoping as saying.

China has imported 60 billion cubic metres of natural gas from Central Asia since 2009, it said.

Mr Xi will join Group of 20 world leaders in St Petersburg beginning Thursday, where one focus will be the slowing growth of China and other major BRICS emerging markets including Brazil, Russia, India and South Africa.

China's economy grew 7.5 per cent from April to June, down from 7.7 per cent in the first quarter of the year.

Late next week in Kyrgyzstan, Mr Xi will meet counterparts from the Shanghai Cooperation Organisation, which is led by China and Russia and includes the four Central Asian nations Mr Xi will visit.

The grouping, set up to counterbalance US and Nato influence in the area, focuses on regional issues including anti-terrorism.