At least eight people have been killed in a suicide bomb attack at the police academy in the Yemeni capital Sanaa, medics and security officials say.
Police sources said the bomber blew himself up among a large crowd of cadets as they left the academy after classes finished for the day.
Initial reports put the death toll at 20, but it was later revised down.
Islamist militants have vowed to launch attacks in retaliation for an ongoing army offensive on their strongholds.
Witnesses said dozens of ambulances rushed to the scene of the attack, which also wounded at least 15 people, according to officials.
"We ran to the place and found dozens of cadets covered in blood. Blood was everywhere. The scene was horrific," police official Fadel Ali told Reuters news agency.
The BBC's Natalia Antelava in Sanaa says there are conflicting reports on whether the suicide bomber was on a motorcycle or on foot, walking among the cadets.
No group has said it carried out the attack, but suspicion fell on a local branch of al-Qaeda.
In May, more than 90 soldiers were killed when a suicide bomber dressed in army uniform blew himself up during a parade rehearsal in Sanaa.
Ansar al-Sharia, an offshoot of al-Qaeda in the Arabian Peninsula, said it had carried out that attack - the deadliest in the capital since Abdrabbuh Mansour Hadi was elected president in February.
The group took advantage of the instability resulting from the popular uprising that forced Mr Hadi's predecessor, Ali Abdullah Saleh, to step down in November after 32 years in power.
After becoming president, Mr Hadi said one of his most important tasks was the continuation of the war on al-Qaeda and he instructed the military to regain control of several key towns in the southern province of Abyan.
Last month, the army recaptured the provincial capital Zinjibar after a campaign which left hundreds of militants and dozens of soldiers dead.
In a separate development on Wednesday, the government announced that it had arrested two of the five al-Qaeda militants who had tunnelled out of a prison in the western province of Hodeida last month.
One of the two men, Nasser Ismail Ahmed Muttahar, was suspected of taking part in an attack on the US embassy in Sanaa in 2008 in which 19 people were killed, including an American woman.