Iran's President Mahmoud Ahmadinejad said Saturday that imposing further sanctions on his country would not deter Tehran from its nuclear program - vowing that such a move would strengthen it.

In an address, Ahmadinejad attacked United States President Barack Obama for not having changed what he called America's policy of hostility toward his country.

"They say they have extended a hand to Iran, but the Iranian government and nation declined to welcome that," he said. "What kind of hand did you extend toward the Iranian nation? What has changed? Did you lift sanctions? Did you stop propaganda? Did you reduce the pressure?"

Ahmadinejad also said that U.S. steps to pressure Iran have backfired and instead have isolated Washington in the eyes of the world.

"Don't imagine that you can stop Iran's progress," Ahmadinejad said. "The more you reveal your animosity, the more it will increase our people's motivation to double efforts for construction and the progress of Iran." The head of Iran's atomic energy agency said Saturday that Tehran was planning to establish two more facilities for uranium enrichment.

Ahmadinejad made his comments in advance of an expected announcement from the permanent members of the United Nations Security Council that it was approaching an agreed-on formula for new sanctions against Tehran.

President Obama held a telephone conversation last Thursday night with China's leader, Hu Jintau, who confirmed he would participate in a Washington conference next week on nuclear issues. Hours after the telephone conversation Obama said in an interview that he intends to step up pressure on Iran. In a CBS interview, Obama said that "the idea is to keep turning up the pressure" on Iran and vowed to do so with the unified backing of the international community.

The U.S. is hoping to be in a position to convince Beijing to support a Security Council resolution of sanctions against Tehran.

After the unusually long telephone conversation between Obama and Hu, a Chinese spokesman said that the nuclear issue "is one of great significance" and reiterated Beijing's opposition to the proliferation of nuclear weapons.

Over the weekend Western intelligence reportedly uncovered Iranian attempts to acquire essential equipment for its nuclear program - bypassing the international sanctions.

According to the Wall Street Journal, a Chinese firm tried to purchase equipment used in centrifuges - which Iran needs for uranium enrichment - on behalf of an Iranian firm.