Berlin - German officials vowed tighter security and called for tougher controls of asylum-seekers Tuesday in the aftermath of four attacks in the country in the span of a week, two of which were claimed by ISIS, the Islamic State extremist group.The attacks left ten victims dead and dozens wounded and have rekindled concerns about Germany's ability to cope with the estimated 1 million migrants registered entering the country last year."The Islamic State is waging a brutal war of aggression ... against our way of life," said Joachim Herrmann, the top security official in Bavaria, where three of the attacks took place.In the most recent attack claimed by ISIS, a Syrian man on Sunday blew himself up outside a crowded music festival in the Bavarian city of Ansbach, wounding 15 people. The man had unsuccessfully tried to find asylum in Germany and was awaiting deportation.In the other attack, a 17-year-old Afghan asylum-seeker wounded five people with an axe before being killed by police near the Bavarian city of Würzburg.In the deadliest attack in the past week, the 18-year-old son of Iranian immigrants went on a rampage at a Munich mall, killing nine people and wounding dozens. Authorities say he was undergoing psychiatric treatment and had no known links to terrorism.Quicker deportationAnd on Sunday hours before the Ansbach attack, a Syrian man killed a woman with a knife in the southwestern city of Reutlingen before being captured by police in an incident authorities say was not believed linked to terrorism.Herrmann said changes need to be made to laws - possibly at the European level - to allow for quicker deportation of people like the Ansbach attacker, while authorities in Germany need to investigate how the man, known as Mohammad Daleel, was able to collect enough material to make at least two bombs in his room in an asylum-seeker home."The people of our country cannot be expected to finance the protection of people who violate the law with their tax money," he said.Most of the immigrants entering Germany last year came through Bavaria, and Bavarian authorities have been particularly critical of Chancellor Angela Merkel's open-door policies. Concerns had died down as the flood of newcomers has slowed dramatically, but the recent attacks have rekindled the debate over how Germany can best cope with the numbers.Speaking alongside Herrmann at a press conference in the town of Gmund am Tegernsee before a state cabinet meeting, Bavarian governor Horst Seehofer and state Justice Minister Winfried Bausback rattled off a laundry-list of proposals, including adding more police, relaxing privacy laws to make it easier for authorities to observe online data like email and WhatsApp and Skype messages, better background checks on asylum seekers, and allowing the military to be called in to help during terrorist attacks."We need to do whatever is necessary to protect our citizens," Seehofer said.Tougher stance In Baden-Württemberg, where a woman was killed by a Syrian attacker on Sunday, Interior Minister Thomas Strobl also demanded a tougher stance toward asylum-seekers."Those who abuse the right to hospitality must go back to their home countries - make no mistake about it," Strobl told Funke media group.On Tuesday, ISIS published a video of what it said was the Ansbach bomber pledging allegiance to the extremist group and vowing 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 suicide bomber's phone and an acquaintance of the attacker verified his voice.In the video, the man, who appears with his face covered with a black scarf, threatens to make life intolerable and that "we will blow up your homes".On the video, the attacker said he acted in response to the extremist group's call to target countries of the US-led coalition fighting it in Iraq and Syria. Germany is not involved in combat operations, but has contributed reconnaissance aircraft to the effort.He threatened that the group would carry out more violence after the bombing in Ansbach, saying "this blessed operation will be followed by others".After the ISIS connection surfaced, federal prosecutors in Karlsruhe, who investigate all suspected terrorism, took over the case saying they would seek to "determine if thus-far unknown accomplices or backers were involved in the crime".A spokesperson for the federal prosecutor's office told The Associated Press that "a main focus is on the question of whether the attacker in Ansbach was helped in the planning and preparation". She spoke on condition of anonymity in line with department policy.Bulgaria, Austria Investigators also need to determine how the video from the attacker got to ISIS and where he learned to build a bomb.The suspect, who is originally from the Syrian city of Aleppo, came to Germany two years ago and applied for asylum in August 2014, Interior Minister Thomas de Maiziere said. It turned out that he had already registered in Bulgaria and later in Austria, so Germany rejected his request and ordered him deported to Bulgaria - most recently on July 13.Asylum-seekers are routinely deported to the first country where they registered if they don't follow proper procedures, even if they're considered to have a legitimate asylum claim.