WASHINGTON, Jan 23 (Reuters) - US Secretary of State Antony Blinken said Sunday (Jan 23) he has "no doubts" Germany is maintaining a united front with NATO on the Ukraine crisis, after Berlin faced pressure to toughen its stance against potential Russian aggression.

The top US diplomat also dismissed the idea of slapping punitive sanctions on Russia now, before any potential invasion of the former Soviet republic Ukraine, saying sanctions should be used as a means of "dissuading" Moscow from an attack.

Blinken's comments follow a week of intense diplomacy in which he held talks with his Russian counterpart and also sat down with German Chancellor Olaf Scholz as Kyiv voiced mounting fears of a Russian invasion.

Germany was in the hot seat at the weekend after its navy chief Kay-Achim Schoenbach said Russian President Vladimir Putin deserves respect and also suggested it was "nonsense" to think Russia was ready to pour troops into Ukraine.

Schoenbach resigned Saturday, but his remarks rattled the North Atlantic Treaty Organization, and Blinken did a round of talk show appearances in a bid to tamp down the worry.

"I can tell you that the Germans very much share our concerns and are resolute and being determined to respond - and to respond swiftly, effectively, and in a united way," Blinken said on NBC talk show Meet the Press.

"I have no doubts about that."

On CBS News show Face the Nation, he also mentioned Germany's commitment to stand shoulder to shoulder with Europe and Washington, saying, "I am very convinced there will be a united response to whatever Russia does.".

With Kyiv facing what Blinken has described as an "unprecedented" threat from Russia, Ukrainian President Volodymyr Zelensky urged Western nations not to delay imposing sanctions on Moscow as a way to prevent an invasion.

"I support imposing sanctions now," Zelensky told the Washington Post on Thursday. "Why do you need sanctions after we lose the whole territory of Ukraine?"

But Blinken dismissed the idea of punishing Russia before any potential invasion of the former Soviet republic, saying the sanctions should be used as a means of "dissuading" Moscow from engaging in further aggression against Ukraine.

"Once sanctions are triggered, you lose the deterrent effect," Blinken told CBS. "So what we're doing is putting together a whole series of actions that would figure into President Putin's calculus."

That includes beefing up defenses in Ukraine with more military assistance, Blinken said.