Afghan President Hamid Karzai, right, is followed by Iranian President Mahmoud Ahmadinejad after giving a joint press conference at the presidential palace in Kabul, Afghanistan on Wednesday. (Musadeq Sadeq/Associated Press)Iranian President Mahmoud Ahmadinejad and a top U.S. official accused each other's countries of having ulterior motives in Afghanistan during separate meetings with Afghan officials on Wednesday.

U.S. Defence Secretary Robert Gates, meeting earlier in the day with Afghan Defence Minister Abdul Rahim Wardak, accused Iran of "playing a double game" in offering aid to Afghanistan while undermining NATO efforts in the country by aiding Taliban-led insurgents.

"It's certainly bothersome," he said. "We think Afghanistan should have good relations with all of its neighbours, but we also want all of Afghanistan's neighbours to play an up-front game in dealing with the government of Afghanistan."

Ahmadinejad fired back, saying during a meeting with Afghan president Hamid Karzai in Kabul that it was the U.S. that was playing a double game.

"They themselves created terrorists and now they're saying that they are fighting terrorists," Ahmadinejad said, a reference to the U.S. funding of Afghan rebels in their fight against the Soviet Union.

"Your country is located on the other side of the world, so what are you doing here?" he asked.

Ahmadinejad says it makes no sense that his country's Shiite-led government would help the fundamentalist Sunni movement of the Taliban.

Iran to assist with reconstruction

The decision to host two diplomatic antagonists on the same day highlights the Afghan government's desire to seek allies wherever it can to strengthen its tenuous hold over the country, where it has been waging a near-constant battle with insurgents.

Karzai said Iran was assisting Afghanistan with reconstruction projects, improving education and helping provide electricity.

"We are very hopeful that our brother nation of Iran will work with us in bringing peace and security to Afghanistan so that both our countries will be secure," Karzai said, adding that Afghanistan has a very good relationship with Tehran.

U.S. Defence Secretary Robert Gates left Afghanistan on Wednesday after a three-day visit to check on the U.S. expansion of its military presence in the country. (Manuel Balce Ceneta/Associated Press)

Yet Karzai's government is also heavily reliant on NATO forces in fighting the Taliban, who were swept from power in 2001 but have remained a presence in both Afghanistan and neighbouring Pakistan.

Afghan Defence Minister Abdul Rahim Wardak said in his meeting with Gates that his country is eager to take over primary responsibility of security in the country, and spoke repeatedly of the goal to expand the army and police forces to a combined 300,000 by the fall of 2011.

Afghan security remains fragile even as NATO forces prepare for a major offensive in Kandahar province later this year.

Attack in Khost province kills 2

NATO reported on Wednesday that an explosion at a police compound late Tuesday in eastern Afghanistan near the Pakistani border killed two NATO service members.

Initial reports from NATO's International Security Assistance Force say a suicide bomber entered the joint Afghan border police-ISAF compound and detonated himself, killing two and injuring several others.

The Chergotah compound where the attack occurred is about 40 kilometres east of Khost city, the capital of the province of Khost.

The Taliban on Wednesday claimed responsibility for the attack.

The bombing is the latest in a string of attacks targeting military or police compounds.

With fiels from The Associated Press