Thorny issues raised alongside pledge on arms pact, a move hailed by China

US President Joe Biden and Russian leader Vladimir Putin held their first conversation as counterparts on Tuesday in a phone call that underscored troubled relations and the delicate balance between the two countries.

White House spokeswoman Jen Psaki confirmed the phone call at her daily news conference. It came as Biden adjusts US policy in a more robust way toward Russia than the one taken by his predecessor Donald Trump.

During their talks, Psaki said, topics included Biden's proposal to extend the Strategic Arms Reduction Treaty, better known as the New START, with Russia for five years and "strong (US) support for Ukraine's sovereignty".

She said the pair agreed to have their teams work to complete the extension of the deal by Feb 5, when the current one expires.

Russian Deputy Foreign Minister Sergey Ryabkov said the two leaders had agreed on the extension of the New START "without preconditions, without any additions, without any appendices whatsoever, as Moscow insisted".

Kremlin spokesman Dmitry Peskov said Putin and Biden expressed satisfaction following an exchange of diplomatic notes on an agreement to extend the treaty.

"Sides will finalize, within days, procedures needed to ensure further functioning of this major international mechanism on reciprocal limitation of nuclear missile arsenals," Peskov said.

"International topics included the United States' unilateral withdrawal from the Open Skies Treaty, problems of keeping in place the Joint Comprehensive Plan of Action on the Iranian nuclear program, Ukrainian settlement, as well as Russia's initiative to call a summit of the United Nations Security Council permanent members."

Zhao Lijian, Chinese Foreign Ministry spokesman, said Beijing welcomes the treaty extension.

The New START will help boost global peace and safety, and it meets the international expectation, Zhao said.

As the US and Russia have more than 90 percent of the world's nuclear weapons, they should fulfill their priority responsibility for nuclear disarmament, Zhao said.

Moscow had reached out last week to request the call, according to US officials familiar with the matter but not authorized to discuss it publicly, The Associated Press reported. Biden agreed, but he wanted first to prepare with his staff and speak with European allies, including the leaders of Britain, France and Germany.

Aside from the European leaders, Biden also phoned NATO chief Jens Stoltenberg before the Putin call. He pledged to uphold the US commitment to the alliance.

'Frank and businesslike'

While the presidents' readouts from the two capitals emphasized different elements, they both suggested that US-Russia relations will be guided－at least at the beginning of the Biden administration－by a desire to do no harm even if there is no urgency to repair existing damage.

According to the White House, Biden also raised concerns about the arrest of opposition figure Alexei Navalny. The Kremlin, meanwhile, said the leaders also discussed other "acute issues on the bilateral and international agenda".

The Kremlin described the talk as "frank and businesslike"－often a diplomatic way of referring to tense discussions. It also said Putin congratulated Biden on becoming president and "noted that normalization of ties between Russia and the US would serve the interests of both countries".