Three police officers and two British soldiers were injured when a blast bomb was thrown at them in north Belfast early this morning.
A PSNI spokesman said a youth threw the device at a police vehicle as it responded to a call in the Whitewell Road area of the city at 4.30 a.m.
A "hostile" group of nationalist youths attacked the officers until assistance arrived, the spokesman added.
The injuries were not believed to be serious and no arrests were made.
The area of the attack is one of the most volatile flashpoint areas of Belfast.
The North's Security Minister Ms Jane Kennedy later condemned the attack as "mindless".
She said: "Attacks on police and security forces are simply unacceptable and will not be tolerated. I would urge community leaders to use their influence to help bring those responsible to justice.
"Anyone with information should tell the police immediately and help us stamp out this unnecessary evil in our society."