BERLIN - German political leaders said it was regrettable that a terror threat had led to the cancellation of a planned march by the anti-Islam movement PEGIDA in Dresden on Monday night, regardless of how one views the group itself.Dresden police have banned all public gatherings in the eastern German city on Monday, including one by the "Patriotic Europeans Against the Islamization of the West" group, which last week attracted a record 25,000 people to its rally.The weekly PEGIDA demonstrations began last October as a local protest against new shelters for refugees and have been growing in size. Counter marches have taken place across Germany with far larger numbers.German Chancellor Angela Merkel has condemned the group as racists "with hatred in their hearts", unusually strong language for the veteran leader."Regardless of how you view the subjects of individual demonstrations, the right to demonstrate is extremely valuable to us, and this can never be restricted lightly," Merkel's spokesman Steffen Seibert said."We have a situation where the responsible authorities in Dresden considered it necessary to take this step. It is a step we will surely want to see as rarely as possible in Germany."PEGIDA leaders said on Monday they would not allow themselves to be muzzled and would plan a rally for next week in conjunction with security officials."The threat wasn't just against me in person, it was also an abstract threat to the demonstration and we have a duty to protect people," said PEGIDA leader Lutz Bachmann.German security authorities said last Friday they had specific warnings of a risk of militant attacks on central railway stations in Berlin and Dresden.Local police, citing information from Germany's BKA federal crime bureau, then said assassins had been called up to mingle among the PEGIDA protesters and murder one of the leaders.PEGIDA leaders deny they are racist and try to distinguish between Islamists and most of Germany's four million Muslims."Whatever you think of PEGIDA, so long as the protest does not break our laws it is protected by freedom of expression rights," said German Justice Minister Heiko Maas."Our democracy can cope with PEGIDA. The vast majority in Germany rejects them and took to the streets in recent weeks to protest against them. This must continue to be possible."