Ahmadinejad tells Karzai he supports the political process in Afghanistan

"The same allegations are made in Iraq. They are saying that they discover some weapons," Mr Ahmadinejad said at a press conference he addressed jointly with President Karzai.

"What is the reason? Why are they saying such things? Iran is a big country. I have serious doubts about this issue," he said.

"With all our force, we support the political process in Afghanistan," Mr Ahmadinejad said.

He added that Iran's security depended on the situation in Afghanistan as the two nations shared a long border.

"For us, a secure and stable Afghanistan is the best," he said.

President Karzai said Afghanistan's ties with Tehran were excellent and addressed the Iranian president as his brother.

Mr Karzai said his country was close to Iran and also a friend and strategic partner of the United States.

"If Afghanistan can bring them [Iran and the United States] closer, that will be a great happiness for Afghanistan - but it depends on both sides," he said.

The appearance of traceable sophisticated weapons and Iranian-produced assault rifles, mortars and plastic explosives in Afghanistan provides evidence of Iran's direct support to the neo-Taliban. Until recently, the explosively-formed penetrators had primarily been seen in Iraq. These weapons, capable of piercing armor, are now being used against NATO forces in Afghanistan, compliments of Iran. If Iran did not want its involvement known it could have supplied untraceable weapons. The introduction of marked weapons into the Afghan theater was purposeful, sending a message of Iran's ability to destabilize western Afghanistan.

Reports of territorial violations also began surfacing earlier this year. Afghan officials accuse their western neighbor of repeatedly violating Afghan airspace as well as of conducting armed incursions into Afghan territory. Furthermore, a former Afghan provincial governor alleges that the Islamic Republic has been hosting a training camp, identified as Shamsabad, for opponents of the Afghan government. These infringements on Afghan sovereignty challenge the efficacy of the central authority in Kabul and its international backers.