Iran's President Mahmoud Ahmadinejad said Tuesday that Iran is to pursue its plan for enriching high-grade uranium for its research reactor, but is still ready to exchange its low-grade uranium for 20 percent uranium fuel.

Iran's President Mahmoud Ahmadinejad attends a press conference in Teheran, capital of Iran, Feb. 16, 2010. [Ahmad Halabisaz/Xinhua]

Ahmadinejad said that his country could not wait longer for the west's response since the fuel of Tehran's research reactor which needs 20 percent enriched uranium is about to finish in the near future.

"We demanded 20 percent uranium fuel from the International Atomic Energy Agency (IAEA) six months ago, but, they did not show readiness to provide Iran with that," Ahmadinejad said in a live press conference broadcast by state IRIB TV.

Iran started the production of 20 percent uranium when the suppliers did not commit to their legal obligations and did not respond to Iran's demand, he said.

However, the file of a nuclear swap "has not been closed," as Iran is still ready to exchange its low-grade uranium for 20 percent uranium fuel with any country, even the United States, said Ahmadinejad.

He also reiterated Iran's insistence that a fuel swap should be done "simultaneously."

Iran's President Mahmoud Ahmadinejad attends a press conference in Teheran, capital of Iran, Feb. 16, 2010. Ahmadinejad said Tuesday that Iran is still ready to exchange its low-grade uranium for 20 percent uranium fuel with any country even with the United States. [Ahmad Halabisaz/Xinhua]

Ahmadinejad, yet, did not rule out the possibility of suspending 20 percent uranium enrichment by Tehran.

"If they (the West) provide the 20 percent uranium fuel, the situation will change (implying the suspension of the process), but if not...we will produce it ourselves and will not wait for them," he said, confirming earlier remarks by head of Atomic Energy Organization of Iran (AEOI) Ali-Akbar Salehi.

Ahmadinejad also announced that Tehran has tested a new generation of advanced centrifuges with a capacity of enriching uranium five times more than the existing ones.

"We have tested new generations of centrifuges that are now in their final phase. Their capacity is five times that of the existing centrifuges," he said signaling that Iran has gained advancements in reaching the superior technology in its nuclear program.

"We will use them for our power plants' fuel in the near future, " the president added.

Asked about probable sanctions by the West, Ahmadinejad said that they had better "to move on the path of cooperation.

"Any decision (to be taken) by them will not cause a problem for us," defiant Ahmadinejad said.

"For sure, if any (country) decide to adopt any measure against Iran, our response...will be retaliative which will make them regret," he added.

The Kremlin on Tuesday urged Iran to improve its cooperation with IAEA, the UN nuclear watchdog, and warned of sanctions if it fails to fulfill its obligations.

Russia's position on sanctions against Iran remained unchanged, Russian President Dmitry Medvedev told visiting Israeli Prime Minister Benjamin Netanyahu on Monday, according to Kremlin spokeswoman Natalia Timakova.

Netanyahu, who is in Russia to push for additional sanctions against Iran over its nuclear program, also said on Tuesday that " crippling sanctions" must be imposed immediately against Iran's energy sector.

"The time to apply sanctions is now, and they should be crippling sanctions," Netanyahu said in an interview with Interfax news agency.?

Ahmadinejad said Thursday that Iran produced first batch of 20 percent enriched uranium under the watch of IAEA.

Last week, Iran handed over a letter to the IAEA, informing it about the Islamic republic's plan to produce 20 percent enriched uranium, provoking fresh warnings from the West of new sanctions.

The United States and its Western allies have been accusing Iran of secretly developing nuclear weapons under the disguise of a civilian program. Iran has denied the accusation and stressed its nuclear program is only for peaceful purposes.