A rebel group in Yemen said it fired a volley of ballistic missiles toward cities in Saudi Arabia late Sunday, including the capital, Riyadh, where at least one person was killed by shrapnel, according to a statement by the rebels and the official Saudi Press Agency.

The Saudi military said it had intercepted seven missiles, including three aimed at Riyadh, where red missile trails were visible in the night sky amid loud booms. The military’s claim could not be independently confirmed. Videos shared on social media appeared to show a projectile — possibly a Patriot missile sent to intercept the incoming rebel fire — crashing to the ground shortly after it was launched.

The rebel group, known as the Houthis, has fired ballistic missiles into Saudi territory repeatedly over the past three years, during a war in Yemen that has pitted the rebels and their allies against Yemeni factions aligned with a Saudi-led military coalition. Saudi and U.S. officials have accused Iran of supplying missiles and other weapons to the Houthis, a charge the government in Tehran has denied.

The multipronged attack Sunday — toward cities in southwestern Saudi Arabia, near the border with Yemen, as well as Riyadh — represented a sharp escalation of the Houthi campaign. It imperiled a fledgling effort by a new U.N. envoy to broker peace talks to end the war and seemed certain to provoke a furious Saudi response.

The attack came on the third anniversary of the Saudi-led coalition’s intervention in Yemen. The coalition, which includes the United Arab Emirates, has been condemned by human rights group for conducting an air campaign that has killed thousands of Yemeni civilians, and enforcing a blockade that has helped cause a vast humanitarian crisis. The United States provides military and intelligence assistance to the coalition.

About 11:28 p.m., loud explosions could be heard across Riyadh, as projectiles — apparently part of a Patriot missile defense system — could be seen streaking upward, until a puff of smoke was visible in the sky. Several other loud booms followed.

As police cars raced across the city, videos shared on social media showed a large missile fragment in the median of a highway, a fiery cascade of debris amid a flurry of Patriot missiles, and what appeared to be a misfire: a missile turning sharply, shortly after it was launched, and slamming into the ground.

Fragments that fell on a house killed one person and injured two others — all Egyptian nationals, the Saudi Press Agency said.

The attack came as Saudi Arabia’s powerful crown prince, Mohammed bin Salman, is conducting a coast-to-coast visit of the United States aimed at courting investors and showcasing what Saudi officials say is an ambitious reform program at home.

While his visit has resulted in a robust debate among U.S. lawmakers over the wisdom of the Trump administration’s continued involvement in Yemen’s war, American officials have resisted calls to reconsider their support for the Saudi-led coalition.