BERLIN (AP) — Germany's domestic intelligence agency said Tuesday it was putting the far-right Alternative for Germany party under heightened scrutiny amid concerns it is flirting with extremism.

The domestic intelligence service BfV plans to examine public comments by Alternative for Germany members and the party's links to extremist groups, but stopped short of putting it under covert surveillance, agency President Thomas Haldenwang told reporters.

The party's youth wing and a party faction linked to a prominent leader in eastern Germany, Bjoern Hoecke, will be scrutinized even more closely, including through the use of covert methods, Haldenwang said.

He cited the party's downplaying of Germany's Nazi period and suggestions from some members it might pursue "revolutionary" means to achieve its political aims as examples of the actions that justified keeping closer tabs on Alternative for Germany, also known by the German acronym AfD.

Alternative for Germany co-leader Alexander Gauland suggested that politics motivated the intelligence service's decision and told reporters the party would take legal action steps.

"We maintain this decision of the BfV is false," Gauland said.

The BfV, which is charged with preventing groups from undermining the German Constitution, has spent months collecting material on Alternative for Germany.

Haldenwang said the agency concluded there was enough evidence that elements of the party were working against some constitutional guarantees, including the dignity of all persons, but had not determined yet whether those activities were representative of the party as a whole.

The party, which placed third in Germany's 2017 national election, has moved steadily to the right since it was founded six years ago as a vehicle for critics of the euro currency.

Several senior figures have quit in recent years, warning Alternative for Germany was being taken over by far-right extremists.

Following reports about possible observation by the BfV agency last year, the party called on members to refrain from making comments that might be considered extremist.

It also expelled three members who attended a neo-Nazi festival where some participants openly displayed support for Nazi leader Adolf Hitler.

A leading member of the center-left Social Democratic Party, Eva Hoegl, said the BfV's decision to more closely scrutinize Alternative for Germany was "right and long overdue."

"Sections of the party have direct links to the right-wing extremist scene and are clearly hostile to the constitution," Hoegl said.