Britain will hold a national minute's silence on Friday to remember victims of the Tunisian beach attack, British Prime Minister David Cameron announced on Monday."We will have a national minute's silence on Friday at 12 noon, one week on from the moment of the attack," said Cameron.

"It is with great sadness that ... we now know at least 18 British nationals have been killed, with more injured and the death toll is likely to rise still further," Cameron added.

According to local media, the number of Britons killed in the Tunisian beach attack was expected to rise to at least 30.

The prime minister described the attack as "brutal and sickening".

"I am sure the whole House will join me in sending our deepest condolences to the families and friends of all those who have lost loved ones," said Cameron.