US President-elect Donald Trump says he is willing to work with Russia and China, providing they cooperate.
Mr Trump told the Wall Street Journal that newly-imposed sanctions on Russia would remain “at least for a period of time” but could then be lifted.
He also said the One China policy, in which the US no longer acknowledges Taiwan, was up for negotiation.
Meanwhile, a US Senate committee will probe claims Russia attempted to meddle in the presidential election.
In his interview, Mr Trump said sanctions on Russia could be lifted if Moscow helped Washington in the war against Islamic extremism and in other matters.
“If you get along and if Russia is really helping us, why would anybody have sanctions if somebody’s doing some really great things?”
He said he hoped a meeting with President Vladimir Putin would be arranged.
With regards to Beijing, Mr Trump said China had to allow US companies to compete by floating its currency.
But he said he would not label China a currency manipulator the instant he took office.
He had already questioned the One China policy last month, provoking angry responses in Chinese state media.
Republican and Democratic leaders on the Senate Intelligence Committee vowed to follow their investigation “wherever it leads”.
They will examine Russia’s cyber activity and intelligence practices.
Interviewees will include members of the current US administration and President-elect Donald Trump’s team.
A statement, released by the committee late on Friday, said: “We believe that it is critical to have a full understanding of the scope of Russian intelligence activities impacting the United States.”
The committee will examine whether there were any contacts between Russia and people associated with the US political campaigns.
It said subpoenas would be issued “if necessary to compel testimony”.