ALMATY - U.S. President Barack Obama plans to visit Kazakhstan as part of a wider tour of Central Asia, Kazakhstan's upper house of parliament quoted him on Tuesday as saying.

The United States embassy in Kazakhstan did not confirm any visit or comment on possible dates.

The United States has stepped up diplomatic activity in the ex-Soviet region this year as it seeks to find alternative supply routes for its troops fighting in nearby Afghanistan.

The Senate upper house said in a statement that Obama met Kazakhstan's speaker Kasymzhomart Tokayev in Istanbul this week and told him he planned to become the first U.S. president to visit the oil-producing nation.

Barack Obama said he planned a tour of our region and will first of all visit Kazakhstan which is a friend and a reliable partner of the United States, the Senate said in a statement.

The United States is the biggest foreign investor in Kazakhstan, Central Asia's biggest oil producer, thanks to energy majors such as Chevron and Exxon Mobil developing large Kazakh oil fields.

Obama's visit would be watched closely by Russia which is nervous about U.S. overtures in a region it sees as part of its traditional sphere of interest.

President Nursultan Nazarbayev, in power since 1989, has sought to develop closer ties with the West while naming Russia and China as equally important partners.

Kazakhstan, along with Russia and Uzbekistan, agreed this year to allow the transit of non-military supplies for U.S. troops in Afghanistan through its territory. At least one batch of cargo has already gone through Kazakh territory.