Two separate attacks killed at least 40 people in Yemen's southern port city of Aden Thursday, one by Iranian-backed Houthi rebels and the other by jihadists, security and medical sources said. Aden is the temporary seat of the country's Saudi-backed government and its supporters in a Saudi-led coalition, which has been fighting Iranian-backed Houthi rebels since 2015. It had seen a year of relative calm.

The first attack was a suicide car bombing carried out by jihadists on a police station, which killed three officers and wounded at least 20 others, including civilians, a security source said.

The second attack was carried out by Iranian-backed Houthi rebels, who used a drone and a ballistic missile to target a parade in a police camp west of Aden and killed at least 30 people, the Reuters news agency reported. Scores more were wounded, medical sources and the rebels said. The targeted forces were loyal to the United Arab Emirates (UAE), a key partner in the Saudi-led coalition, the Associated Press reported.

The internationally recognized Yemeni government established its headquarters in Aden after Houthi rebels forced it out of the capital Sanaa in 2015.

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In January last year, the city was rocked by deadly clashes that saw southern separatists seize much of it from other pro-government forces.

The UAE is a key partner in the Saudi-led coalition which is fighting the Iranian-backed Houthi rebels, and has enforced an air and sea blockade on rebel-held areas and carried out a controversial bombing campaign that has exacted a heavy civilian death toll.

In recent months, the rebels have hit back with missile and drone attacks targeting neighboring Saudi Arabia.

Several rounds of UN-brokered talks, including an accord reached in Stockholm in December, have failed to end the fighting.

The conflict has killed or wounded tens of thousands of people and resulted in the world's worst humanitarian crisis, according to the United Nations.

An estimated 24 million Yemenis -- more than 80 percent of the population -- depend on some form of humanitarian assistance for survival, UN agencies say.