Dhaka, March 17 -- The United States will keep attacking Yemen's Houthis until they end attacks on shipping, the US defense secretary said on Sunday, as the Iran-aligned group signaled it could escalate in response to deadly US strikes the day before.

The airstrikes, which the Houthi-run health ministry said killed at least 53 people, are the biggest US military operation in the Middle East since President Donald Trump took office in January. One US official told Reuters the campaign might continue for weeks.

Houthi leader Abdul Malik al-Houthi said on Sunday that his militants would target US ships in the Red Sea as long as the US continues its attacks on Yemen. "If they continue their aggression, we will continue the escalation," he s...