Iranian foreign ministry expressed concerns about the strategic partnership agreement signed by the United States and Afghanistan, local satellite Press TV reported on Sunday.

Foreign Ministry spokesman Ramin Mehmanparast said that the unclear roles defined for U.S. forces and their military bases in the pact are major sources of concerns for Iran and other regional countries, said the report.

The pact cannot resolve Afghanistan's security problems; instead, it will further destabilize the country and increase insecurity, Mehmanparast was quoted as saying.

Iran believes a complete withdrawal of foreign forces and closure of their military bases is the only way to solve Afghanistan's problems and to bring peace and security to the country, said Mehmanparast.

Afghanistani President Hamid Karzai on Thursday assured the country's neighbors that signing strategic partnership with the United States does not pose any threat to them. "There is no threat from Afghanistan soil to our neighbors," Karzai told journalists at a press conference just one day after inking the pact with his U.S. counterpart President Barack Obama.

Obama paid a surprise visit to Kabul late Tuesday night. During his tour, Obama inked the strategic pact with Karzai and visited main U.S. military facilities in Bagram.

Karzai said that under the pact, the United States needs to support Afghanistan in all fields including economy and security.

According to Karzai, Afghanistan wants to further enhance relations with both Pakistan and Iran. He added that the U. S.-led coalition forces should pursue terrorists hiding in sanctuaries outside the Afghan borders, instead of fighting them in Afghan villages.