If confirmed, a strike reaching Riyadh would mark a significant widening of the conflict beyond Saudi Arabia's southern border region, and oil traders will treat it as a test of how exposed the kingdom's core infrastructure has become. That matters because Saudi export capacity, including the East-West Pipeline that has only just returned to near-normal flows, is central to the recovery in Middle East supply. Until Saudi authorities confirm or deny the claims, any price reaction is likely to reflect headline risk rather than lost barrels, adding to the premium that has kept Brent around $100. Confirmation of damage or civilian casualties would raise the risk of a stronger Saudi military response, which could escalate further. An official statement that projectiles were intercepted would likely see some of that premium fade.---Earlier:US oil inventory preview: five terms to know before Wednesday's EIA dataOil: Hormuz tanker captains offered about $100,000 a month as crews weigh war riskOil: Private survey of inventory shows a headline crude oil draw--- The Houthis say they have struck the Saudi capital, but until Riyadh confirms it, oil markets are trading a claim, not a confirmed attack.Summary:Yemen's Houthis said they attacked King Khalid International Airport in Riyadh, Abha Airport and an air base at Khamis Mushait using drones and ballistic missilesSaudi authorities had not confirmed any of the claims at the time of writing, and there were no reports of damage or casualtiesThe claims follow confirmed attacks on Saudi airports in Jazan and Najran on Monday evening that injured three peopleFighting has escalated as Saudi-backed Yemeni government forces press an offensive against the Houthis, backed by Saudi airstrikesA confirmed strike on Riyadh would mark an expansion of the conflict well beyond Saudi Arabia's southern border regionYemen's Iran-backed Houthis said they launched drone and ballistic missile attacks on three targets in Saudi Arabia, including King Khalid International Airport in the capital Riyadh. Saudi authorities had not confirmed any of the claims, and there were no independent reports of damage or casualties.The group said it targeted the Riyadh airport and Abha Airport in the southwest, and an air base at Khamis Mushait in the same region. Accounts of the weapons used differed slightly: initial Houthi statements said ballistic missiles and drones were used against Abha, while a later summary referred to drones for both airports.The claims should be treated with caution until they are verified. The Houthis have a long record of announcing strikes on Saudi targets that were later reported by Saudi authorities as intercepted or that caused little damage. Saudi air defences routinely engage incoming drones and missiles, particularly in the southern provinces bordering Yemen.Even unconfirmed, the claims add to a sharp escalation in recent days. On Monday evening, Saudi airports in Jazan and Najran were targeted in two attacks that injured three people and caused limited damage, according to the Saudi aviation authority. That fighting has intensified as Saudi-backed Yemeni government forces push a major offensive to retake territory from the Houthis after weeks of rebel advances, with Riyadh stepping up airstrikes in support.A successful strike on Riyadh would represent a notable widening of the conflict. Abha and Khamis Mushait lie in the southwest, within easier reach of Houthi forces, whereas the capital is far from the Yemeni border and home to key government and economic infrastructure.For oil markets, the timing is sensitive. Saudi Arabia has only just restored flows through its East-West Pipeline to the Red Sea export hub of Yanbu to close to 6 million barrels a day, and Middle East crude exports had been recovering. Repeated attacks on Saudi territory risk undermining confidence in that recovery and helping to keep a geopolitical premium in prices.The key test will be whether Saudi Arabia confirms the attacks, reports interceptions or remains silent, and whether any damage or casualties emerge in the coming hours. This article was written by Eamonn Sheridan at investinglive.com.