Yesterday’s claims that the Chinese government had, after months of US cajoling, finally agreed to support sanctions against Iran appear to be premature, and China has reiterated its past position that diplomacy, not sanctions, should resolve the issue.
The UK's "Guardian" got caught with its journalistic pants down when it made the claim as reported on 31 March as reported at:
"China supports Barack Obama's call for new Iran sanctions"
"According to officials with knowledge of the talks, an agreement to begin drafting a security council resolution was reached in a telephone call involving representatives of the US, China, Russia, Britain, France and Germany."
Note that these "officials" were never sourced.