US officials say President Joe Biden is pressing national security agencies to develop new strategies to counter the dangerous entrenchment of ties between Russia, Iran, North Korea and China ahead of President-elect Donald Trump's inauguration next month.

According to Reuters, Biden concluded - in a "secret" national security memo issued yesterday, Tuesday - that Russia is providing its ally Iran with fighter jets, missile defense systems, and space technology in exchange for its assistance in the war effort in Ukraine.

Russia also supplies North Korea with fuel, money and technology, and recognizes it as a de facto nuclear state, and the US administration has said that Russia conducts joint patrols with China in the Arctic.

Russia, China, Iran and North Korea have previously challenged similar assessments, accusing the United States of destabilizing behavior.

In the new document, Biden orders various arms of the US government to restructure groups currently organized by region, to better focus on issues that connect the four countries, and extend across Europe and Asia.

Republican Trump, who takes office on January 20, may implement the strategies and policies proposed in the document, or reject them entirely.

New options

"When the new team sees the document, I don't think they will see anything in it that will push them toward a particular policy option," said a senior administration official.

Another official said they wanted to present "new options so the new team and Congress can get to work quickly."

The challenges ahead, the officials added, include ensuring that any sanctions or export restrictions imposed on the four countries are implemented in a coordinated manner that doesn’t risk negative reactions from those countries, and enabling the United States to better deal with simultaneous crises involving several of those countries. There are North Korean troops in Russia, for example.

“We are in a world where our adversaries and competitors are learning from each other very quickly,” one official said.

Another official said cooperation between the countries had limits, however, as shown by the failure of Russia and Iran to help their ally, former Syrian President Bashar al-Assad, who was ousted by the opposition over the weekend.

"This change raises questions for China about what kind of future it wants and whether it really wants to be part of this group," he added.