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Hani Mohammed, Associated Press
Men look at a car destroyed by a recent Saudi-led airstrike in Yemen's capital, Sanaa, Saturday, April 25, 2015. With combatants fighting in neighborhoods and Saudi-led coalition warplanes pounding Iran-backed rebels from the sky, Yemen's war is wreaking a particularly bloody toll among civilians: more than 550 have been killed in the past month, including 115 children, the U.N. said Friday.

SANAA, Yemen — Aircraft from the Saudi-led coalition battling Shiite rebels in Yemen struck targets in several cities on Sunday, including the capital, security officials said, as fighting raged across the country.

The continued airstrikes and combat between rival factions on the ground underline how a negotiated peace remains elusive in the Arab world's poorest country. They also come despite a Saudi announcement last week saying coalition operations would scale down and shift to focus on diplomacy, humanitarian and counter-terrorism issues.

The Sunday airstrikes began just after midnight, officials said, hitting a military base known to be an arms depot on the outskirts of Sanaa, as well as sites near the presidential palace where weapons were being moved.

In the southern port city of Aden, they said air raids targeted the rebels, known as Houthis, as street fighting between them and forces loyal to exiled President Abed Rabbo Mansour Hadi continued. They spoke on condition of anonymity because they were not authorized to brief journalists.

The Houthis are allied with military units loyal to former President Ali Abdullah Saleh against the coalition and pro-Hadi forces. Although Hadi is Yemen's internationally recognized leader, he was forced to flee his stronghold of Aden last month as the Houthis advanced toward the port. The Saudi-led coalition began conducting airstrikes against rebel positions a day later on March 26.

Hadi is now in the Saudi capital of Riyadh. The Houthis still control much of the country.

Also Sunday, pro-Saleh forces battled tribesman in the central Marib province, where coalition airstrikes also hit targets. The officials added that the jets also struck pro-rebel sites in Shabwa and Lahj provinces.

The Sunni Arab countries in the coalition and their Western supporters say the Houthis get their arms from Shiite powerhouse Iran. Tehran and the rebels deny that, although the Islamic Republic has given political and humanitarian support to the Shiite group.

The United Nations said Friday that the war is causing a particularly bloody toll among civilians, killing over 550 of them in the past month, including 115 children.