Iran's foreign minister said he is optimistic the U.S. relationship with other countries can improve under the new U.S. president, Barack Obama.

Manouchehr Mottaki on Wednesday welcomed President Obama's desire to open a dialogue with Iran.  But Iran's foreign ministry spokesman, Hassan Qashqavi, added that if talks are to happen, Washington needs to stop accusing Iran of wrongdoing.

Washington suspects Iran is trying to build nuclear weapons, and it is looking for ways to persuade Tehran to stop enriching uranium, a key element in nuclear bombs. Iran insists its nuclear program is for peaceful, civilian purposes.

Iranian President Mahmoud Ahmadinejad said on Tuesday that Tehran was ready for talks with Washington in an atmosphere of "mutual respect."

The remarks signal a significant softening of tone between the United States and Iran, which severed ties 30 years ago.

Iran's foreign minister also said Wednesday that there was no reason to continue trilateral talks with the U.S. and Iraq because of Iraq's improved security conditions.

Mottaki spoke at a news conference in Baghdad, where he is leading a high-level delegation focused on trade and other cross-border cooperation.

Washington has held several rounds of Iraqi security talks with Iranian officials in Baghdad.

Tehran has opposed a U.S.-Iraqi security agreement allowing American troops to remain in Iraq through 2011. Iran has said the deal undermines Iraqi sovereignty.

The U.S. Defense Department issued a report last month accusing Iran of hosting, training, funding, arming and directing militant groups intent on destabilizing Iraq.

Iran dismisses U.S. claims it is fostering unrest in Iraq.