Wen Jiabao, the Chinese premier, has made it clear he does not agree with Western demands for sanctions over Tehran's disputed nuclear programme, insisting he will maintain "close co-operation" with Iran.

Oil exports account for nearly half of Iran's revenues - being cut off from the West means most is exported to Asian countries – and a big percentage of that to China.

In return China is investing billions in Iran's gas and oil fields.

And as Al Jazeera's Nazanine Moshiri reports from Tehran, the Iranian capital, their trade links are becoming stronger.