A man holds a sign as he protests ISIS at New York's Time Square, the United States, March 22, 2016. The Islamic State (IS) has claimed responsibility for Tuesday's terror attacks in Belgian capital of Brussels, which killed at least 34 people and injured more than 100. [Photo/Xinhua]

BRUSSELS - The Islamic State issued two videos on Friday warning that the "nightmare" of the Brussels terror attacks "had only just begun", Belgian broadcaster RTBF reported on Saturday.

The videos were sent to Belgian newspaper Le Soir, showing two radical militants ordering western governments to withdraw their troops from Syria and Iraq, RTBF reported.

"Tell them to withdraw their planes and soldiers and you will live in peace," a speaker says in one of the videos.

"The nightmare has only just begun. What will come later will be even more appalling," the video continued.

"Remember my message a year ago when it was announced that we would attack Paris and Brussels. We have achieved that and we have other targets," the video added.