German Chancellor Angela Merkel warned her coalition partners advocating a Greek exit from the euro to “weigh their words,” as she signaled a renewed determination to keep the single currency intact.

Asked about comments by a leader of her Bavarian Christian Social Union governing partner calling for Greece to depart, Merkel told ARD television that such remarks were damaging as crisis fighting has reached a “decisive phase.” Alexander Dobrindt, the CSU’s general secretary, told today’s Bild newspaper that Greece wouldn’t be part of the 17-nation euro area next year.

“Everybody should weigh their words very carefully,” Merkel told ARD on Sunday in Berlin. The Greek government under Prime Minister Antonis Samaras is undertaking “serious efforts” to reduce its debt, she said, and repeated that Germany will stand by the country where the crisis originated.

Merkel also called the permanent bailout fund, the European Stability Mechanism, “absolutely necessary” to overcome the crisis and signaled that she’s confident that the Federal Constitutional Court will approve the measure when it decides on the matter on Sept. 12.

“I think we’ve brought forward good arguments” for the ESM, Merkel said, alluding to the euro-area’s fiscal pact.

The German leader said the European Central Bank has a “very clear” mandate to ensure the single currency’s stability and that any plan decided under ECB President Mario Draghi will conform with that mandate.

Responding to criticism over sovereign debt purchases made by Bundesbank President Jens Weidmann, Merkel said she welcomed input from Germany’s central bank

“I think it’s a good thing that Jens Weidmann continues to make demands on policy makers,” Merkel told ARD.

Weidmann told today’s Der Spiegel magazine that a proposed new wave of sovereign bond purchases by the ECB may increase governments’ reliance on such funding and won’t help solve the euro-area debt crisis.

“We shouldn’t underestimate the danger that central bank financing can become addictive like a drug,” Weidmann said in an interview with Spiegel. “Such policy is too close to state financing via the money press for me.”

[Bloomberg]