LONDON (AP) -- Britain's Prime Minister David Cameron has postponed a key speech on Europe because of the hostage crisis in Algeria.

Downing Street said Thursday that Cameron will stay in Britain to oversee the situation unfolding at a natural gas plant in the Sahara Desert. Algerian forces launched a military assault on Thursday to try to free dozens of foreign hostages, including an unknown number of Britons.

Cameron called the crisis in Algeria a "difficult, dangerous and potentially very bad situation."

The prime minister was to make his long-awaited speech in Amsterdam on Friday about how he thinks Britain's relationship with the EU should change, a move that many fear could backfire and leave Britain increasingly isolated in Europe.