The Latest on the influx of migrants into Europe (all times local):

12:45 p.m.

The European Commission says Greece's response to the refugee emergency continues to be too slow and that it's not sending enough migrants who don't qualify for asylum back home.

A report released Wednesday said that the deployment of specialist teams known as hotspots to register and fingerprint migrants has been held up in part by staffing and infrastructure shortages.

The commission's report said that "only one hotspot is currently fully operational." The hotspot scheme was launched in September and Greece is supposed to have five up and running.

The report noted that almost 20,000 migrants have been deported since the beginning of last year, but that "this remains insufficient in the context of over 800,000 arrivals in 2015."

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10:15 a.m.

Police say a recent grenade attack on an asylum seekers' home in Germany wasn't triggered by hatred on refugees, but suspect it was caused by rivalry between different companies involved in providing safety for asylum centers.

Police in Villingen-Schwenningen in the Black Forest said late Tuesday that they detained four suspects. They did not reveal names of the four men, but only said they were migrants from eastern Europe.

Police did not give any further details, but said "conflicts between security companies could be the cause" for the attack.

The grenade was thrown over the fence of the asylum home the night of Jan. 28-29 and landed next to the container of the security staff. It didn't explode, and a bomb squad destroyed it in a controlled explosion.