Russia and China leaders to meet at security summit

But Iranian President Mahmoud Ahmadinejad, facing new U.N. sanctions targeting Tehran's nuclear program, is unlikely to attend the Shanghai Cooperation Organisation meeting in Uzbekistan, two sources told Reuters.

The six-nation SCO, led by Russia and China, will meet in the Uzbekistan's capital Tashkent on Thursday, a day after the United Nations Security Council is expected to approve fresh sanctions against a defiant Iran. The regional security bloc, which also includes four ex-Soviet Central Asian states, will discuss the fight against terrorism and extremism as well as drug trafficking from Afghanistan. Afghan President Hamid Karzai has been invited.

Ahmadinejad has stolen the limelight before at major conferences, including an SCO meeting in Shanghai in 2006 that was dominated by news about Iran's nuclear program.

When the grouping met in Russia last year, SCO leaders congratulated Ahmadinejad on his disputed re-election in what was seen as a snub to the West.

Iran has observer status in the SCO and a Chinese official had said Ahmadinejad might attend. But Iran's ambassador to Tajikistan, where Ahmadinejad was attending a water conference, said on Wednesday that the president would not participate.

"President Ahmadinejad is not going to the summit in Tashkent. Instead he is leaving Dushanbe on Thursday morning to Shanghai" for the World Expo, ambassador Ali-Asghar Sherdoost told Reuters.

A source in the Kremlin also said he would not attend.
Clashes Over Sanctions
Russia and Iran have close ties but have clashed over Kremlin support for fresh U.N. sanctions, which would call for measures against new Iranian banks abroad if a connection to nuclear programs is suspected.

Russia and China, veto-wielding U.N. Security Council members, have worked to water down the sanctions and are expected to vote in favor.

Ahmadinejad on Tuesday warned the Kremlin against siding with "Iran's enemies" in supporting sanctions. The Kremlin reacted to similar comments in May by telling Iran's leader to refrain from "political demagoguery."

The absence of the Iranian leader will allow the SCO's members -- China, Kazakhstan, Kyrgyzstan, Russia, Tajikistan and Uzbekistan -- to focus on regional security issues.

"The SCO has plenty of its own problems to be dealing with: extremism, separatism, the threat of militancy and drug trafficking from Afghanistan," said Kazakh political analyst Dosym Satpayev.

The political situation in Kyrgyzstan, where the president was overthrown in April, will be discussed, the Kremlin press service said in a statement. Interim foreign minister Ruslan Kazakbayev will represent Kyrgyzstan at the meeting.

The Kremlin source said Medvedev would meet Karzai and leaders from Pakistan, which also has observer status. His meeting with Chinese President Hu Jintao would focus first and foremost on Korean tensions, the source said.

Hu will also meet Kazakh President Nursultan Nazarabayev in Astana on Friday and is likely to seek cooperation in combating "East Turkestan" separatism, Chinese assistant foreign minister Cheng Guoping said.

Kazakhstan borders Xinjiang, the frontier region of China that is home to the Uighurs, a central Asian people who chafe at religious and linguistic restrictions of Chinese rule and at economic policies favoring Chinese migrants and corporations.

China blames separatists for unrest in the region, including riots last July that grew out of protests over the killing of Uighur migrant workers in southern China.