Schools and the subway system remained closed Tuesday as Brussels, Belgium, remained under tight security while authorities tried to find the key suspect in the November 13 Paris attacks.
Brussels Remains on High Alert

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The military presence in Brussels appeared lighter on Tuesday as schools prepared to reopen on Wednesday, Nov. 24, 2015.

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Police and soldiers guard Brussels' main train station, which is still open for passengers coming in from out of town, Nov. 24, 2015.

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Belgian tourism businesses said they have been receiving numerous calls from people canceling their visits in December. Photo taken Nov. 24, 2015.

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Tanks were moved from Brussels' famed Grand Palace on Tuesday, but a few armed soldiers remain, Nov. 24, 2015.