The Latest on a series of attacks in Germany (all times local):

9:45 a.m.

Top security officials in Germany are calling for tougher security screening of asylum-seekers and have also announced that more police officers will be hired following four attacks in the country — two of them claimed by the extremist Islamic State group.

Horst Seehofer, the interior minister of Bavaria — where three of last week's attacks took place — told the daily Sueddeutsche Zeitung Tuesday: "we must know who is in our country."

Thomas Strobl, the interior minister of Baden-Wuerttemberg — where a woman was killed by a Syrian attacker Sunday — also demanded a tougher stance toward asylum-seekers.

Three of the attacks were carried out by recent immigrants, rekindling concerns about Germany's ability to cope with the estimated 1 million migrants registered entering the country last year.

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9:05 a.m.

The extremist Islamic State group has published a video in which a man pledges allegiance to IS and vows Germany's people "won't be able to sleep peacefully anymore." It appears to be the same as the one found by German investigators on the phone of man who blew himself, killing himself and wounding 15 people.

The IS-linked Aamaq news agency released the video early Tuesday. The man on the video, his face covered with a black scarf, threatens to make life intolerable and that "we will blow up your homes."

German authorities could not immediately be reached to confirm whether the video was the same as the one found on the cell phone of a 27-year-old Syrian who blew himself Sunday night in the Bavarian town of Ansbach.