ZURICH—Switzerland is banning Islamic State and related organizations in the country, a move that comes as the Alpine nation steps up measures to prevent Swiss citizens from traveling to the Middle East to fight for the extremist group.

On Wednesday, the Federal Council, Switzerland’s seven-member cabinet, said a ban on membership of Islamic State, which is also known by the acronyms ISIS and ISIL, will go into effect on Thursday. The ban will last for an initial six months.

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