Iranian President Mahmoud Ahmadinejad denied on Tuesday U.S. accusations his country was arming Taliban insurgents in neighbouring Afghanistan.

U.S. officials say Iranian weapons are entering Afghanistan on such a scale it is hard to believe Tehran is not aware of the shipments. High-powered roadside bombs, which Washington says Iran sends to Iraq, have also begun to appear in Afghanistan.

Asked about the accusations, Ahmadinejad told a news conference in the Afghan capital, Kabul: "I strongly doubt that, there is no truth in it... even in Iraq such claims are made."

Ahmadinejad was in Afghanistan just a week after Afghan President Hamid Karzai returned from a visit to Iran's arch foe, the United States, where President George W. Bush warned his guest that Iran was "not a force for good".

The United States accuses Iran of arming militant groups throughout the Middle East, attempting to destabilise its neighbours Iraq and Afghanistan and seeking to develop a nuclear arsenal, all charges Tehran denies.

Karzai's pro-Western government has rarely criticised Iran, with which it shares a long and porous border and enjoys strong trading ties.

"We strongly support the political process of Afghanistan," Ahmadinejad said. "The security of Afghanistan has a primary impact on Iran because we have long borders. For us, a strong and stable Afghanistan is the best option."

AFGHAN BRIDGE

The Iranian president blamed the West for terrorism.

"The Afghan and Iranian governments are both victims of terrorism. Terrorism is supported by super-powers," he said.

Shi'ite Iran almost went to war with the staunchly Sunni Taliban movement when it controlled Afghanistan in the late 1990s, but Western analysts say Tehran has an interest in making life uncomfortable for U.S. troops by arming its former foe.

Karzai said his country might be able to bridge the divide between the United States and Iran, at odds since the Iranian revolution deposed the U.S.-backed shah in 1979.

"Afghanistan has strong ties with Iran, we share the same religion and language. Also, we are a strategic partner of the United States," Karzai told the news conference.

"If Afghanistan can bring these countries closer together, it will be a great happiness for Afghanistan... but it all depends on what those two nations think," he said.

Iran is host to some 1 million Afghan refugees and migrant workers, but has angered Afghan leaders by deporting some 160,000 Afghans since April, often without allowing them to take any of their belongings or savings with them.

Afghan authorities and international agencies are struggling to cope with the influx and many returnees are living in temporary accommodation while others were deported by Iran into areas of conflict with Taliban insurgents.

"There are 2.5 million Afghans living in Iran right now, they have (the) same rights, we have no problems. We have problems with those who enter Iran illegally through our borders, naturally they create problems," Ahmadinejad said.