China has expressed strong dissatisfaction with and firm opposition to Washington's sanctions on China's Bank of Kunlun, Foreign Ministry spokesman Qin Gang said in a statement on Wednesday.

The sanctions on the Chinese bank seriously violate international norms and harms China's interests, and China will raise solemn representations to the United States, Qin said.

US President Barack Obama announced additional sanctions against Iran's energy and petrochemical sectors on Tuesday in response to the Islamic republic's disputed nuclear program.

The US Treasury Department targeted a Chinese bank and an Iraqi bank for "knowingly" enabling financial transactions for blacklisted Iranian banks, said Xinhua News Agency.

China and Iran enjoy normal relations and open business cooperation, and China has no relation with Iran's nuclear program, which does not violate United Nations Security Council resolutions or harm the interests of a third party, Qin said.

"China has been consistent and clear regarding its position on non-proliferation. It firmly maintains the principles of the international non-proliferation system and commits itself with parties involved, including the US, to solving the Iranian nuclear issue," the spokesman said.

"But the US has ignored China's concerns and repeatedly imposes sanctions against Chinese enterprises and banks. This will negatively affect Sino-US bilateral cooperation.

"China urges the US to correct its erroneous decision, lift the unprovoked sanctions against the Bank of Kunlun and stop harming Chinese interests and Sino-US relations."

The Bank of Kunlun belongs to China National Petroleum Corporation, and its main clients include large State-owned enterprises, companies and staff members in energy and petrochemical industries.