China’s imports of Iranian oil spiked to record 874,000 barrels per day in August, ahead of US plans to sanction Iran's energy sector, leading market news provider Platts has reported.

Citing new figures, the agency said the arrivals last month took inflows from Iran over January-August to 165.57 million barrels, 72% of total Iranian crude imports of 229.99 million barrels over full year 2017.

Chinese refiners Sinopec and PetroChina told Platts they would not let the US sanctions affect their intake of the Iranian crude.

"Since we have performance obligations under our Iran-related contracts in 2018, we are contractually required to continue our [purchases]," Sinopec said.

A Sinopec executive said last week that the company's business would be hurt if it had to suspend imports from Iran. Sinopec's dependence on Iranian crude, he said, is “natural” because many Chinese refineries were so configured to process Iranian oil, which has a rich aromatics content.

According to Platts, China is expected to remain the biggest buyer of Iranian crude despite the sanctions. Beijing itself has asserted it would not let the bans come in the way of its trade with Iran.

The US says the sanctions will take effect on November 4, and has warned countries that they would face “secondary” bans if they continued to buy Iranian oil in defiance of the measures.

This is the second round of sanctions the US imposes against Iran since its withdrawal in May from a multilateral nuclear deal with the Islamic Republic.

Aside from China, Turkey has said it would not submit to the oil embargo. Other countries such as Japan and India have been trying to obtain waivers from the bans.