At least six civilians, including women and children, were killed and dozens wounded in Saudi-UAE-led coalition air raids on residential areas and Houthi rebel military targets in Yemen's capital, Sanaa.
The coalition carried out 11 attacks on the capital in all, out of a total of 19 across rebel-held territory on Thursday, the Houthi-run Masirah TV channel reported. It blamed "aircraft of the [Saudi-led] aggression".
The air strikes came two days after the Iran-aligned rebels claimed drone attacks that temporarily shut a key oil pipeline in neighbouring Saudi Arabia.
Rubble filled a populated street lined by mud-brick houses, a Reuters journalist on the scene said. A crowd of men lifted the body of a women, wrapped in a white shroud, into an ambulance.
Saudi-owned broadcaster Al Arabiya quoted a coalition statement as saying it launched an operation aimed at "neutralising the ability of the Houthi militia to carry out acts of aggression".
"The sorties achieved its goals with full precision," it said, adding civilians had been warned to avoid those targets.
Masirah quoted the Houthi health ministry as saying six civilians, including four children, had been killed and 52 wounded, including two Russian women working in the health sector.
A witness told AFP news agency that raids began around 8am (05:00 GMT).
Afrah Nasser, a Yemeni journalist, said her family's home in Sanaa was near where one air strike hit. She accused the Saudi-UAE alliance of deliberately targeting civilians.
"I know the street. There are no military targets there. There is no excuse from the Saudi-led coalition - it was a deliberate and systematic bombardment attacking civilians," Nasser told Al Jazeera.
Nasser Arrabyee, another Yemeni journalist, said the number of casualties was expected to rise.
"Medical sources are saying that they have received a lot of victims - injured and dead - which means the number will be even higher than just six," he told Al Jazeera from Sanaa.
"Residential areas in the middle of Sanaa, in the most crowded areas, were randomly bombed and many houses were reduced to the ground."
Calls for retaliation
On Tuesday, the Houthi rebels claimed responsibility for twin drone attacks on Saudi Arabia's main East-West oil pipeline, saying they were a response to "crimes" committed by Riyadh during the bloody air war it has led in Yemen since March 2015.
Saudi Arabia's deputy defence minister accused Iran on Thursday of ordering the drone attacks on two Aramco pumping stations as a "tool to implement its expansionist agenda in the region".
"The terrorist acts, ordered by the regime in Tehran, and carried out by the Houthis, are tightening the noose around the ongoing political efforts," Prince Khalid bin Salman said on Twitter.
The head of the Houthis' Supreme Revolutionary Committee denied that Iran directed the strike and said the movement manufactures its drones locally. Tehran also denies providing arms to the Houthis.
"We are not agents for anyone," Mohammed Ali al-Houthi said. "We make decisions independently and do not take orders for drones or anything else."
The Saudi pipeline, which can carry five million barrels of crude per day, provides a strategic alternative route for Saudi exports if the shipping lane from the Gulf through the Strait of Hormuz is closed.
Iran has repeatedly threatened to close the vital conduit for global oil supplies in the case of a military confrontation with the United States.
The Saudi cabinet called on Wednesday for "confronting terrorist entities which carry out such sabotage acts, including the Iran-backed Houthi militias in Yemen".
Key ally the United Arab Emirates (UAE) echoed the call.
"We will retaliate and we will retaliate hard when we see Houthis hitting civilian targets like what happened in Saudi Arabia," the UAE minister of state for foreign affairs, Anwar Gargash, said on Wednesday.