(Adds quotes, background)

TEHRAN, Aug 28 (Reuters) - Iranian President Mahmoud Ahmadinejad said on Tuesday the power of the United States was rapidly collapsing in Iraq and that Iran was ready to step in to help fill the vacuum.

"The political power of the occupiers (of Iraq) is being destroyed rapidly and very soon we will be witnessing a great void of power in the region," Ahmadinejad told a news conference.

"We, with the help of regional friends and the Iraqi nation, are ready to fill this void," he said.

Iran, which is also at loggerheads with the United States over Tehran's disputed nuclear programme, has repeatedly blamed the presence of U.S. forces in Iraq for violence threatening to tear the country apart.

For its part, the United States is accusing Iran of fomenting instability in Iraq by supporting militias there, a charge Tehran rejects.

Ahmadinejad said: "They (the United States) are trapped in the swamp of their own crimes and have no choice but to accept the failure and accept the independence and rights of the Iraqi nation.

"If you stay in Iraq for another 50 years nothing will improve, it will just worsen," he said.

AlertNet news is provided by