A Yemeni health official says that along with the 51 killed, as many as 56 were wounded in Thursday's attacks.
Rebels in Yemen fired a ballistic missile on Thursday at a military parade in the southern port city of Aden and coordinated suicide bombings targeted a police station in another part of the city. The attacks killed at least 51 people and wounded dozens, officials said.
The missile hit in the city's neighbourhood of Breiqa where a military parade was underway by forces loyal to the United Arab Emirates, a member of the Saudi-led coalition that has been fighting the Iran-backed Houthi rebels since 2015 in support of Yemen's internationally recognised government.
The missile attack killed at least 40, a health official said.
The parade was taking place at the pro-coalition al Galaa camp in Aden, said a security official, without giving a breakdown for the casualties. Since the rebels seized the country's capital, Sanaa, in 2014, Aden has served as the temporary seat of the government.
The website of the Houthi rebels, Al Masirah, quoted spokesman Brig. Gen. Yehia Sarea as saying the rebels had fired a medium-range ballistic missile at the parade, leaving scores of casualties, including military commanders.
The security official told The Associated Press that UAE-backed commander Monier al Yafie, also known by his nickname Aboul Yamama, was among those killed.
He was delivering a speech during the parade, the official said.
TRT World's Francis Collings has more.
A short while earlier, a car, a bus and three motorcycles laden with explosives targeted a police station in the city's Omar al Mokhtar neighbourhood during a morning police roll-call, said Abdel Dayem Ahmed, a senior police official.
Four suicide bombers were involved in the attack, which killed 11 and wounded at least 29, Ahmed told the AP.
No group immediately claimed responsibility for the police station bombings but both Yemen's Al Qaeda branch and Daesh affiliate have exploited the chaos of the country's war between the Houthis and the government forces, backed by the Saudi-led coalition.
A Yemeni health official said that along with the 51 killed, as many as 56 were wounded in Thursday's attacks. Both the security and health official spoke on condition of anonymity because they were not authorised to talk to reporters.
Charred remains of the attackers' vehicles were seen at the scene of the police station attack, next to a meter-deep crater caused by the bombings.
Doctors Without Borders tweeted that dozens of wounded were transferred to the aid group's surgical hospital in Aden, where families of the victims had gathered.
Zakarya Ahmed, a senior police officer who was inside the three-story station when the bombings took place, described the attack as "a disaster."
"I felt myself flying in the air and falling down, hitting the floor," Ahmed said. "When I got up on my feet, I saw bodies burning, others torn into pieces."
Thursday's attacks were the deadliest in Aden since November 2017, when the Daesh affiliate in Yemen targeted the city's security headquarters, leaving 15 dead, mostly policemen.
Deputy Interior Minister Ali Nasser Lakhsha told reporters as he inspected the site of the bombed-out police station that it was unclear who was behind the assault.
"This is a horrific terrorist attack targeting our police," the minister said.
The attackers' motorcycles were still burning as blood pooled on the staircase of the police station and the street outside was littered with shattered glass and debris from blown-out doors and windows.
War in Yemen
The conflict in Yemen began with the 2014 takeover of Sanaa by the Houthis, who drove out the internationally recognised government.
Months later, in March 2015, a Saudi-led coalition launched its air campaign to prevent the rebels from overrunning the country's south.
In the relentless campaign, Saudi-led airstrikes have hit schools, hospitals and wedding parties and killed thousands of Yemeni civilians. The Houthis have used drones and missiles to attack Saudi Arabia and have also targeted vessels in the Red Sea.
Thursday's attacks in Aden came just weeks after the UAE began withdrawing thousands of its troops from Yemen, leaving behind what it says are some 90,000 trained local forces.
The UAE also has high level commanders and forces in Yemen, but has pulled back 50-75 percent of its forces, insiders have said.
The UAE pullout came against the backdrop of escalating tensions in the Persian Gulf amid a crisis between Washington and Tehran following the US pullout last year from the nuclear deal with Iran.
For its part, Iran has repeatedly denied supplying the Houthis with drone or ballistic missile technology, both of which the rebels have increasingly used, including to target neighbouring Saudi Arabia.
The kingdom has claimed that Iran supplied the missiles or at least helped the Houthis manufacture them from parts that were in Yemen before the war.