Iran's Foreign Ministry spokesman Ramin Mehmanparast reiterated on Tuesday his country's concerns over the security pact recently signed between the United States and Afghanistan.

The Islamic republic has informed the Afghani officials about its concerns over the agreement, said Mehmanparast in his weekly press briefing.

Peace, stability and security in Afghanistan is highly important for Iran, and Afghanistan's security is intertwined with the security of the whole region and Iran. Any instability or insecurity can leave its impact on the Islamic republic, said the Iranian spokesman.

"We believe the presence of foreign forces, including the U.S. forces and its allies is the root cause of insecurity and instability in the regional countries and especially in Afghanistan," said Mehmanparast.

He stressed that the regional countries can assist the establishment of security in Afghanistan.

On Sunday, Mehmanparast said that the unclear roles defined for U.S. forces and their military bases, in the strategic partnership agreement between the United States and Afghanistan, are major sources of concerns for Iran and other regional countries.

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

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, he added.

Afghanistani President Hamid Karzai last 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 one day after inking the pact with his U.S. counterpart Barack Obama.

Obama paid a surprise visit to Kabul, the capital of Afghanistan, last 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.