Originally Published: 02 MAR 23 07:15 ET

Updated: 02 MAR 23 07:59 ET

By Jennifer Hansler and Kylie Atwood, CNN

(CNN) -- US Secretary of State Antony Blinken met with Russian Foreign Minister Sergey Lavrov on Thursday for the first time since the war in Ukraine began more than a year ago.

The brief contact on the sidelines of the G20 Foreign Ministers meeting in New Delhi marks a significant moment as high-level engagements between the United States and Russia have become exceedingly rare since the start of the war last February. Blinken and Lavrov's meeting comes amid some of the most heightened tensions between Washington and Moscow in decades.

Blinken initiated the meeting and according to a State Department official traveling with the top US diplomat, the two spoke for roughly 10 minutes.

The top US diplomat called on Russia to "End this war of aggression. Engage in meaningful diplomacy that can produce a just and durable peace."

"President Zelensky has put forward a 10 point plan for a just and durable peace. The United States stand ready to support Ukraine through diplomacy to end the war on this basis," Blinken said at a press conference later on Thursday.

"President Putin, however, has demonstrated zero interest in engaging, saying there's nothing to even talk about unless and until Ukraine accepts and I quote 'the new territorial realities,' while doubling down on his brutalization of Ukraine."

US has 'directly raised' concerns with China that it could provide weapons to Russia

Blinken said the US and its allies have "directly raised" with China their concerns that Beijing will provide lethal assistance to Russia.

Blinken noted that "this is a shared concern ... And many other partners have raised this and not just raised this with us, but it's my understanding have raised it directly with China, including here today in Delhi," he said.

The top US diplomat again warned that "this would be a serious problem for us in our relationship with China."

"And I made clear that there would be consequences for engaging in those actions. So I'm not going to detail what they would be. But of course, we have sanctions authorities of various kinds. That would certainly be one of the things that we and others would look at," he said.

Blinken raised Russia's decision to suspend its participation in a key nuclear arms control treaty.

"I urged Russia to reverse its irresponsible decision and return to implementing the New START treaty, which places verifiable limits on the nuclear arsenals of the United States and the Russian Federation. Mutual compliance is in the interest of both our countries. It's also what people around the world expect from us as a nuclear powers," Blinken said.

"I told the foreign minister that, no matter what else is happening in the world or in our relationship, the United States will always be ready to engage and act on strategic arms control, just as the United States and Soviet Union did even at the height of the Cold War," Blinken said.

'Serious proposal' on Paul Whelan

Blinken added he "raised the wrongful detention of Paul Whelan as I have on many previous occasions."

"The United States has put forward a serious proposal. Moscow should accept it," he said.

Whelan, a former marine who is a US, Irish, British and Canadian citizen, was detained at a Moscow hotel in December 2018 by Russian authorities who alleged he was involved in an intelligence operation. He was convicted and sentenced in June 2020 to 16 years in prison in a trial US officials denounced as unfair.

Elizabeth Whelan, Paul Whelan's sister, told CNN following Blinken's exchange with Lavrov that "of course, we are pleased to see Paul's case elevated in this manner, and take a great deal of comfort in the fact that the Secretary of State continues to press for a solution to Paul's wrongful detention."

But there aren't high expectations the meeting will lead to a breakthrough on key issues of tension between the countries.

"I wouldn't say that coming out of this encounter there was any expectation that things will change in the near term," the State Department official told the traveling press.

Blinken approached Lavrov on the sidelines of the meeting, according to both the State Department official and Russian Ministry of Foreign Affairs spokesperson Maria Zakharova.

"Blinken asked for contact with Lavrov," Zakharova told CNN. "Sergey Viktorovich (Lavrov) spoke on the go, as part of the second session of the twenty [G20], there were no negotiations, meetings, etc."

The last time Blinken and Lavrov met in person was in Geneva last January -- just weeks before the Russia invaded Ukraine. Blinken and Lavrov were both present at several meetings together over the past year, but had not spoken with each other on those occasions.

As recently as Wednesday, Blinken suggested he would not meet with his Russian counterpart at the meeting in the Indian capital.

"No plans to see either at the G20, although I suspect that we'll certainly be in group sessions of one kind or another together," Blinken said at a press conference Wednesday, referencing both Lavrov and Chinese Foreign Minister Qin Gang.

The two spoke by phone last July for the first time since the start of the war. In that "frank and direct conversation," Blinken said he "pressed the Kremlin to accept the substantial proposal that we put forth on the release of Paul Whelan and Brittney Griner," the latter of whom was freed in a prisoner swap in December.