China’s Ministry of Commerce said on Saturday it had issued an injunction to block U.S. ​sanctions imposed on five Chinese refiners accused ‌of buying Iranian oil, according to state news agency Xinhua.

The ministry named the five as Hengli Petrochemical (Dalian) Refinery, and ​the so-called 'teapot' refineries Shandong Jincheng Petrochemical Group, Hebei ​Xinhai Chemical Group, Shouguang Luqing Petrochemical and Shandong ⁠Shengxing Chemical.

In April, the U.S. Treasury imposed sanctions ​on Hengli Petrochemical, accusing it of buying billions ​of dollars in Iranian oil, in an escalation of Washington's long-running effort to curb Tehran's oil revenue.

The Trump administration last year ​imposed sanctions on the other four refineries named ​by the ministry, among others.

The U.S. sanctions violate "international law and ‌the ⁠basic norms of international relations," the ministry said.

As a result, the ministry said, it had imposed an injunction.

"The injunction stipulates that the United States cannot recognise, ​implement, or comply ​with the ⁠sanctions imposed on the aforementioned five Chinese companies," added the ministry.

The sanctions created ​some hurdles for the refiners, including ​difficulties receiving ⁠crude and having to sell refined products under different names. Teapots account for a quarter of Chinese ⁠refinery ​capacity, operate with narrow and sometimes ​negative margins and have been squeezed recently by tepid domestic demand.

- Reuters