Dozens of Russian diplomats expelled from the United States as punishment for Moscow's alleged interference in the White House election landed back in Moscow Monday, Russian state media said.

The envoys were ordered out of the U.S. in retaliation for what the Obama administration said were cyber-attacks directed by “the highest levels of the Russian government.”

The diplomats and their families departed Washington's Dulles International Airport on Sunday and arrived in Moscow early Monday, according to Russia's state-run TASS news agency.

On arrival, the diplomats' children were invited to the Kremlin's New Year and Christmas celebrations, TASS reported.

Meanwhile, Russian President Vladimir Putin condemned the expulsion but declined his own foreign minister's guidance to retaliate, choosing not to expel American diplomats stationed in Russia.

He also invited the children of the American diplomats to the Kremlin's party.

According to The Guardian, Putin said his government would wait to see how relations developed under the incoming president, Donald Trump, who later described the Russian leader in a tweet as “very smart.”

“We will make further steps to help resurrect Russian-American relations based on the policies that the administration of Trump will pursue,” the Russian president said in a statement on the Kremlin’s website.

Putin, mindful that Trump will be in the White House in just three weeks, went on in an almost teasing way to wish Barack Obama and his family, and Trump and the American people a happy new year. He invited “all the children of American diplomats accredited in Russia to the New Year and Christmas celebrations in the Kremlin”.

His stance appeared to be warmly welcomed by the president-elect, The Guardian said.

President Barack Obama ordered the diplomats' out of the country Thursday.  He also imposed sanctions on two suspected hackers and three companies that allegedly provided support to cyber operations by Russia's GRU intelligence service.