'Let it be an arms race'

President-elect Donald Trump indicated Friday he did not fear a new arms race and warned the United States would match any move by another country to boost its nuclear arsenal, in a spectacular new foray into foreign policy.

His stunning -- and initially unexplained -- use of language reminiscent of the Cold War rocked the Washington establishment two days before Christmas, and left Americans baffled by the seemingly mixed messages Trump is sending Russia.

Trump began upping the nuclear rhetoric with a bombshell tweet Thursday calling for America to "greatly strengthen and expand its nuclear capability until such time as the world comes to its senses regarding nukes."

Anti-proliferation campaigners and lawmakers were aghast at the saber-rattling talk, though some observers wondered how much stock to put into Trump's words -- and even whether they may be part of a deliberate strategy to bring about a promised rapprochement with Russia.

His remarks came hours after President Vladimir Putin declared Russia needs to "strengthen the military potential of strategic nuclear forces," and a day after the president-elect met with Pentagon brass.

When asked for clarity, Sean Spicer, the incoming White House press secretary, said Trump would not tolerate other countries increasing their nuclear arsenal without responding.

Early Friday, Trump was quoted telling MSNBC -- when asked in an off-air telephone call to clarify his nuclear policy tweet -- that his administration had no reservations about entering "an arms race."

"This morning he told me on the phone, 'Let it be an arms race. We'll outmatch them at every pass and outlast them all,'" network host Mika Brzezinksi said.

Ties between Moscow and Washington hit their lowest point since the Cold War under Obama due to the Ukraine crisis and Russia's military intervention in Syria.

Even as the country reeled from his Twitter outburst, Trump sowed further confusion Friday by releasing a copy of what he called a "very nice letter" in which the Kremlin strongman offered him Christmas greetings and called for greater bilateral cooperation.

Trump has often said he admires Putin's leadership qualities and the US intelligence community concluded that Russia was responsible for cyber attacks ahead of November's election that sought to tip the balance in favor of the Republican.

Democratic Congressman Brad Sherman, a senior member of the House Foreign Affairs Committee, suggested something more was at play between Trump and Putin.

"One possibility is that this isn't all nonsense or even a mistake, but rather is part of a choreographed effort" between Putin and Trump, he said on MSNBC.

"One could imagine that they simply re-sign the START treaty, tell us, 'Look, we solved this nuclear problem or at least played it down, and now is the time to eliminate sanctions and make other concessions to Russia.'"