India, China and Japan are among eight countries temporarily allowed to continue buying Iranian oil as they showed significant reduction in oil purchase from the Persian Gulf country after the US reimposed crippling sanctions on Tehran, Secretary of State Mike Pompeo said on Monday.

US Secretary of State Mike Pompeo

Washington:

Pompeo vowed that the US will be "relentless" in pressuring Iran as he announced the list of the countries temporarily exempted from the US sanctions during a press conference broadcast live.

Italy, Greece, South Korea, Taiwan and Turkey also figure in the list released by Pompeo, who said over 20 countries have cut their oil imports from Iran, reducing purchases by more than one million barrels per day.

The US on Monday imposed "the toughest ever" sanctions on a defiant Iran aimed at altering the Iranian regime's "behaviour". The sanctions cover Iran's banking and energy sectors and reinstate penalties for countries and companies in Europe, Asia and elsewhere that do not halt Iranian oil imports.

While the US had previously wanted countries including India to completely halt oil purchases from Iran by November 4, it seems to have relented considering the havoc the move to completely take out Iranian supplies from the market would have had on prices.

India, the world's third-biggest oil consumer, meets more than 80 per cent of its oil needs through imports. Iran is its third-largest supplier after Iraq and Saudi Arabia and meets about 10 per cent of total needs. Currently, India pays its third largest oil supplier in euros using European banking channels.

India has resisted Washington's call to reduce purchases to zero, citing the galloping energy needs of its 1.3 billion people. But at the same time, India has taken steps to reduce its oil purchase from Iran, which has already declined substantially.

In May, President Donald Trump pulled the US out of the 2015 landmark Joint Comprehensive Plan of Action (JCPOA) terming it as disastrous". Under the Obama-era deal, involving five permanent members of the UN Security Council and Germany, Iran agreed to stop its nuclear programme in exchange for relief from economic sanctions.

After the US' withdrawal from the deal, Trump signed fresh sanctions against Iran and warned countries against any cooperation with Tehran over its controversial nuclear weapons programme.

Iran has dismissed these charges and maintains that its nuclear programme is for peaceful purposes.

Iranian oil is a lucrative buy for refiners as the Persian Gulf nation provides 60 days of credit for purchases, terms not available from suppliers of substitute crudes -- Saudi Arabia, Kuwait, Iraq, Nigeria, and the US.