Yemen’s Houthi rebels said on Tuesday they targeted a Saudi oil tanker in the Red Sea with ballistic missiles for violating a blockade on the kingdom’s ports announced by the group.

“The targeting of the Saudi vessel came after it ignored warnings,” a Houthi military spokesman said, identifying the ship as the NCC Ghazal and adding it had been “forced to turn back”.

The website MarineTraffic, owned by maritime tracking firm Kpler, listed the Ghazal as a Saudi-flagged tanker whose last known location was the port of Yanbu, the terminus of an important oil pipeline on the kingdom’s Red Sea coast.

Last week, the Iran-backed Houthis declared a maritime blockade of Saudi Arabia and have since claimed attacks targeting Saudi tankers and oil infrastructure.

The blockade has threatened Saudi Arabia’s ability to get its supplies to the world following Iran’s parallel blockade of the Strait of Hormuz, the kingdom’s only other maritime route.

Riyadh last week struck Houthi targets in Yemen in response to the threats to Red Sea shipping.

A Saudi-led military coalition had fought against the Houthis in support of Yemen’s internationally recognised government after war broke out in the country in 2015.

The latest flare-up marks the first time in years that Saudi Arabia and the rebels have traded blows, threatening a 2022 truce in the previous conflict that has held despite expiring.