Iranian President Mahmoud Ahmadinejad and his Chinese counterpart, Hu Jintao, are due to meet Friday in Shanghai for talks likely to focus on Iran's controversial nuclear program.

China and the four other permanent U.N. Security Council members, plus Germany, have offered Iran incentives intended to persuade it to stop enriching uranium and begin negotiations.

Mr. Ahmadinejad is an observer at the summit of the Shanghai Cooperation Organization, where he met Thursday with Russian President Vladimir Putin.

Mr. Putin later said Iran is responding positively to the international incentives offer. Mr. Ahmadinejad called on Central Asian nations to support his country in the dispute over its nuclear program.

In Washington, a White House spokesman Tony Snow said Iran will try at the Shanghai summit to test the unity of the six world powers that approved the incentives package.

In Tehran, supreme leader Ayatollah Ali Khamenei said Iran will not abandon its nuclear research, calling it a fundamental and basic right.

The U.S. delegate to the International Atomic Energy Agency, Gregory Schulte, said the international community agrees that Iran has not taken the steps necessary to prove its nuclear program is entirely for peaceful purposes.

Recent reports by the I.A.E.A. say Iran is continuing to obstruct inspections of its nuclear sites, which could eliminate doubts about the true nature of Tehran's nuclear program.

Some information for this report provided by AP and AFP.