BERLIN - Germany will have to go its own way on immigration if it cannot get other European Union states to sign up to migrant return deals, Interior Minister Horst Seehofer said, in remarks that could shatter a fragile peace in the government.Chancellor Angela Merkel's government teetered on the brink of collapse last week as Seehofer's Bavarian conservatives demanded a unilateral tightening of German border controls that she was prepared to concede only in the framework of a European agreement.The coalition partners seemed to resolve the tensions - at least on migration - on Thursday, with the centre-left Social Democrats agreeing to allow expulsions of some asylum-seekers provided bilateral agreements were in place with the EU states where they had first applied for asylum.But in an interview with news magazine Der Spiegel, extracts of which were published on Friday, Seehofer once again threatened to act unilaterally if Germany could not seal the promised deals with other EU countries."It wouldn't be a good strategy to assume that there are going to be no bilateral agreements," he said. "Then we'd have to go back to the plan of turning people away at the border."Merkel, whose decision to open Germany to about a million people seeking asylum in 2015 fuelled the rise of anti-immigration parties, rejects unilateral expulsions as going against the spirit of European cooperation.Seehofer has drawn broad criticism. On Friday, about 40,000 people had signed a petition calling for his resignation that was posted by a Berlin social worker on the change.org website around midday.Greens party leader Robert Habeck told the tageszeitung newspaper that Seehofer had disqualified himself as a minister by putting a personal feud over German stability."After the past days of chaos, the interior minister has a lot of work to do," Burkhard Lischka, a Social Democrat interior affairs spokesman, told the Rheinische Zeitung newspaper.Christian Lindner, head of the pro-business Free Democrats, said the migration row had tarnished Germany's reputation, but would also cost Seehofer's Christian Social Union its absolute majority in a Bavarian regional election this October."It takes more than sauerkraut, lederhosen and coarse slogans to impress Bavaria," he told broadcaster Deutschlandfunk. "There are many cosmopolitan people who do not share the crude views that are being expressed."Seehofer, scrambling to shore up his party before the Bavarian election and stop bleeding votes to the anti-immigration Alternative for Germany, has staked his political future on ensuring tighter controls.The Bavarian leader, whose party has for decades been in a sometimes fractious conservative alliance with Merkel's Christian Democrats, was in Vienna on Wednesday to discuss return agreements with Austrian Chancellor Sebastian Kurz.