Afghan President Hamid Karzai has arrived at the US presidential retreat at Camp David outside Washington, for a two-day summit with President George Bush.
In an interview broadcast on CNN before his arrival Sunday, Mr. Karzai said he plans to discuss Afghanistan's worsening security situation with President Bush.
The Afghan leader said he does not blame neighboring Iran for the rising number of suicide bombings and attacks on US-led coalition forces.
He said Iran has been more of "a helper and a solution" to Afghanistan's problems than a hindrance.
His position contrasts sharply with the Bush administration, which has blamed Iran for bankrolling terrorists and supplying arms to militants in Afghanistan and Iraq.
Mr. Karzai said Afghanistan is investigating reports that Iran is arming insurgents but said his government will continue to have "good relations" with Tehran.
Mr. Karzai said the two days of talks with Mr. Bush are likely to center around continuing efforts to combat terrorism, the drug trade, and how to reduce Afghan civilian casualties in coalition bombing raids on insurgents.
They also are expected to discuss the situation of 21 South Korean hostages in Afghanistan. Kabul is refusing Taleban demands for the release of jailed militants in exchange for the South Koreans abducted more than two weeks ago.
South Korea has appealed to Kabul and Washington for help in securing the safe release of the hostages, most of whom are female. The Taleban has killed two male hostages, and has warned more hostages could be killed.