The United States called Wednesday for a united front with China against Iran's nuclear program as it debates whether to slap sanctions on the Asian power over oil purchases from the Islamic republic.
The United States has exempted 18 nations but not China from tough sanctions that come into effect on June 28 on countries that buy oil from Iran, which Israel and some Western officials accuse of building a nuclear weapon.
Kurt Campbell, the top State Department official on East Asia, said that the United States and China were "right in the middle" of talks about Iran and did not answer a question on whether Beijing would receive an exemption.
"We have underscored how important it is to have a solid, unified international consensus about how to deal with the challenges posed by Iran's nuclear program," Campbell said at the Center for a New American Security, a Washington think-tank.
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But Campbell welcomed China's efforts in the so-called P5+1 -- a group comprising Britain, China, France, Germany, Russia and the United States that is negotiating with Iran over its nuclear program.
"I must say we have thanked China for their support within the P5+1 and we will continue close consultations with them going forward," he said.
China has defended its oil purchases, saying that they were legal and transparent and criticizing the United States for imposing sanctions unilaterally instead of working through the United Nations.
The sanctions would bar business with financial institutions of countries that do business with Iran's central bank, which handles oil transactions, effectively forcing a choice between operating in Iran or the United States.
On Monday, Secretary of State Hillary Clinton exempted emerging economies including India -- which was initially angered by the US law but has pledged to cut oil purchases from Iran, which with New Delhi has traditionally warm ties.
Iran says that its nuclear program is for peaceful purposes. US intelligence, while critical of Iran, has not concluded that the regime is building a nuclear weapon.