[Migrants stroll between barracks at the camp for refugees in Friedland]By Noah Barkin BERLIN (Reuters) - German authorities are investigating 40 cases in which Islamic militants are suspected of having entered the country with the recent flood of refugees from the Middle East, the federal police said on Wednesday. In the past, the German government has played down the risks of Islamic State fighters entering Europe with the tide of migrants, in part to avoid exacerbating public concerns about the influx, which hit a record 1.1 million last year. PARIS ATTACKS The number of migrants entering Germany reached peaks of more than 10,000 a day last autumn, but has fallen dramatically in recent months due to the closing of the Greek border with Macedonia and a deal between the European Union and Turkey that has discouraged refugees from crossing the Aegean Sea.