Eurostar have said snow and ice in the UK and northern France were leading to speed restrictions and delays on all its trains.
Six services were also cancelled, with customers told they could exchange their tickets for another date.
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The Islamic centre where the Manchester suicide bomber is thought to have prayed says the attack "has no place in Islam or any religion".
German chancellor Angela Merkel and Indian prime minister Narendra Modi among those to praise "great spirit" of Manchester people.
The bomber's identity has been confirmed by Greater Manchester Police.