Calling Ukraine’s leader “a modern-day hero,” U.S. Rep. Doug Lamborn said President Volodymyr Zelensky’s private video call with U.S. lawmakers Saturday morning conveyed the urgency of responding quickly as the Russian invasion of its European neighbor enters its 11th day.

Lamborn, a Colorado Springs Republican and a member of the Congressional Ukrainian Caucus, took part in the hourlong Zoom call along with nearly 300 senators, fellow House members and their aides.

“He is showing so much bravery, along with the Ukrainian people, and that comes through with everything he says,” Lamborn told Colorado Politics. “It felt like I was part of history, being able to interact with him.”

Lamborn said the U.S. should facilitate efforts to transfer military aircraft from nearby Eastern European countries to Ukraine in response to Zelensky’s plea, though the lawmaker expressed skepticism about establishing a NATO-enforced no-fly zone.

“He said they need airpower. The Russians dominate in the air, and they need aircraft,” Lamborn said, noting that ground-to-air Stinger missiles supplied to Ukraine by the U.S. have a limited range, leaving the Ukrainian Air Force heavily overmatched by the Russians.

“He said that, or he wants a no-fly zone – either of those two things, aircraft or a no-fly zone,” Lamborn said. “And those are both hard things to do in the middle of a war. In fact, I’m not even sure we can do a no-fly zone without getting into a war with Russia ourselves.”

Russian President Vladimir Putin said on Saturday that Moscow would consider any third-party declaration of a no-fly zone over Ukraine as “participation in the armed conflict,” The Associated Press reported.

NATO has refused Zelensky’s recent requests for a no-fly zone, saying the likelihood of direct military confrontation with nuclear-armed Russia could provoke a widespread war, a conclusion Lamborn said he shares.

Another member of Colorado’s congressional delegation, U.S. Rep. Jason Crow, participated in the videoconference with Zelensky but declined through a spokeswoman to comment on what was said during the call.

The Centennial Democrat – like Lamborn, a member of the House Armed Services Committee and the Congressional Ukrainian Caucus – took to Twitter on Saturday, however, to rebuke fellow lawmakers who ignored a reported request from the Ukrainian ambassador at the beginning of the meeting to refrain from posting anything during the call in order to protect Zelensky from threats of assassination.

“The lack of discipline in Congress is truly astounding,” wrote Crow. “If an embattled wartime leader asks you to keep quiet about a meeting, you better keep quiet about the meeting. I’m not saying a damn thing. Lives are at stake.”

Republican U.S. Sens. Marco Rubio of Florida and Steve Daines of Montana came under heavy criticism for posting screenshots of Zelensky speaking on the call during the Zoom meeting. Other lawmakers described the call and its contents in social media posts and interviews after it had concluded.

Calling Rubio and Daines “two great guys,” Lamborn told Colorado Politics he wasn’t aware of the controversy over their posts and said he was “hesitant to criticize them,” adding, “Hopefully, it’s just an oversight, but it does run the risk of a security breach. My understanding is there are assassins looking for Zelensky right now.”

Zelensky, who opened the call by telling lawmakers it could be the last time they see him alive, made clear the heavy toll the invasion has taken on civilians, Lamborn said.

“He first talked to us about some of the atrocities and, frankly, war crimes that the Russians are committing, including – maybe not intentionally, but they’re ending up killing a lot of men, women and children,” Lamborn said.

The U.N. human rights office said Saturday that it has confirmed the deaths of 351 civilians in Ukraine since the Russian invasion began, along with 707 civilians injured, the AP reported. The office said it believes the actual figures are considerably higher because confirming casualties in areas with intense fighting has been delayed.

Lamborn reiterated his support for a U.S. ban on importing oil from Russia, something else Zelensky told lawmakers will help his country defend itself from the Russian invasion. Lamborn said he doesn’t understand why the Biden administration has been resisting the ban, which has gained widespread, bipartisan support, including from Colorado’s two Democratic U.S. senators, Michael Bennet and John Hickenlooper.

“Seems to me he’s putting domestic political considerations above the survival of a democratic country,” Lamborn said, referring to Biden.

While Lamborn suggested that the administration is worried about provoking a backlash from American consumers if a ban increases prices at the pump, officials have said they’re concerned the move would drive the worldwide price of oil higher, which could result in rewarding Russia if it’s able to evade sanctions and sell its oil elsewhere.

In addition, Lamborn said it’s time for Biden to reverse his decision to shut down the Keystone XL pipeline, which would move oil from Canada to the Gulf Coast for refining, and to allow more drilling on federal lands.

Hours after the call, Hickenlooper posted to Twitter that he had taken part in the meeting.

“The U.S. unequivocally stands with Ukraine,” he wrote. “We need to send humanitarian aid and ban Russian oil imports.”

Lamborn said he was encouraged at the broad support among his colleagues for standing with the U.S. ally.

“I think everyone is supportive, and that’s heartening to see – it’s very bipartisan – to see this support for Ukraine,” he said.

When asked what average Coloradans can do to help, Lamborn said, “Keep Ukrainians in your thoughts and prayers, and if called upon to sacrifice through higher gas prices, know it’s for a very good cause.”

– Gazette editor Vince Bzdek and The Associated Press contributed to this story.