The U.S. government on Wednesday returned the Yemen-based Houthi rebels to a list of terrorist groups in the latest attempt by Washington to stem attacks on international shipping, Ednews reports citing Reuters.

Officials said the "Specially Designated Global Terrorist" (SDGT) designation, which hits the Iran-aligned group with harsh sanctions, was aimed at cutting off funding and weapons the Houthis have used to attack or hijack ships in vital Red Sea shipping lanes.

"This designation is an important tool to impede terrorist funding to the Houthis, further restrict their access to financial markets, and hold them accountable for their actions," White House National Security Advisor Jake Sullivan said in a statement.

"If the Houthis cease their attacks in the Red Sea and Gulf of Aden, the United States will immediately reevaluate this designation," Sullivan said.

President Joe Biden's administration also issued "carve outs" aimed at avoiding an impact on Yemen's population, which relies on food imports and humanitarian aid, and pledged to conduct outreach to groups including aid agencies before the designation comes into effect in 30 days.

Biden last week called the Houthis a "terrorist" group. American and British warplanes, ships and submarines have launched dozens of airstrikes targeting the Houthis, who control the most populous parts of Yemen.

The U.S. military on Tuesday carried out its latest strike against four Houthi anti-ship ballistic missiles, two U.S. officials told Reuters.

Houthi spokesperson Mohammed Abdulsalam on Wednesday told Reuters that the designation would not affect operations, which the group says are in support of the Palestinians and target Israeli ships or ships heading to Israel.

"We will continue to counter and blunt Iranian malign influence wherever we can. So of course the choice to move away from Iran is now in the hands of the Houthis," said one of three administration officials who briefed reporters ahead of the announcement on condition of anonymity.

A Saudi Arabia-led military coalition intervened in Yemen in 2015, backing government forces fighting the Houthis in a war widely seen as a proxy conflict between U.S. ally Saudi Arabia and Iran.