Yemen’s Houthi movement claimed on Thursday that it fired a ballistic missile at King Khalid International Airport in Riyadh, in what would be one of the boldest strikes of the group’s campaign against Saudi Arabia.

The Saudi-led coalition responded that its air defences had intercepted two missiles heading toward Riyadh and a third toward Khamis Mushait. The coalition did not report any damage or casualties from Thursday’s interception.

The claim comes in an already deadly week. Three people were killed in earlier attacks, including an Egyptian and an Algerian national at Abha airport and a Sudanese national in Riyadh, according to regional reports.

The escalation has drawn in other regional players. Pakistan has confirmed that its troops are stationed in Saudi Arabia, while Syria is said to be weighing how it might assist Riyadh.

The Red Sea corridor and Saudi cities have faced repeated Houthi missile and drone attacks over the course of the conflict. Each round of claims and interceptions raises the stakes for oil markets and for millions of civilians living within range.