After a quiet Christmas Day, President Trump on Tuesday returned to two of his favorite vacation activities: tweeting and golfing.

Trump began his day criticizing the FBI and claiming that the now-famous dossier containing allegations about his connections to Russia and possible coordination between his campaign and the Kremlin during the 2016 election is a "pile of garbage."

Trump, who is vacationing at his Mar-a-Lago estate here, appeared to be watching and quoting from the morning cable-news show "Fox & Friends" while tweeting.

"WOW, @foxandfrlends 'Dossier is bogus. Clinton Campaign, DNC funded Dossier. FBI CANNOT (after all of this time) VERIFY CLAIMS IN DOSSIER OF RUSSIA/TRUMP COLLUSION. FBI TAINTED.' And they used this Crooked Hillary pile of garbage as the basis for going after the Trump Campaign!" he tweeted, referring his followers to a misspelled Twitter account that is unrelated to the TV show.

The Hillary Clinton campaign and the Democratic National Committee helped fund the research that resulted in the dossier, which was first published by BuzzFeed in January.

Officials have said some of the information it contains has been corroborated, but other parts — including the most salacious claims about Trump's behavior — remain unverified.

Trump and some congressional Republicans are ramping up their criticism of the FBI, in an apparent effort to discredit special counsel Robert S. Mueller III and his investigation into possible coordination between the Trump campaign and Russia.

On Christmas Eve, Trump attacked FBI Deputy Director Andrew McCabe, who plans to retire amid increasing criticism from Republicans, for his role in the investigation into Hillary Clinton's use of a private email server while she was secretary of State. Trump and his supporters have claimed McCabe and other FBI officials are biased against him.

Trump had no public events on his schedule Tuesday, and he headed out to Trump International Golf Club shortly after sending his morning tweets.

He golfed there with Sen. David Perdue (R-Ga.), PGA Tour player Bryson DeChambeau and former Professional Golfers' Association player Dana Quigley.

Perdue and Sen. Tom Cotton (R-Ark.) have introduced a bill endorsed by Trump that aims to slash legal immigration levels in half over a decade by creating a "merit-based" immigration system that would put a greater emphasis on the job skills of foreigners over their ties to family in the United States.

News of Trump going golfing drew scrutiny from his critics, who were quick to charge Trump was not living up to his Christmas Day tweet that on Tuesday he would be "back to work in order to Make America Great Again (which is happening faster than anyone anticipated)!"

Trump has hit the links three of the five days he has been in town. Saturday, his first full day here, Trump played a round with pro golfers Jim Herman, Daniel Berger and Justin Thomas, as well as Thomas's father, all of whom are friends of Trump's, according to the White House.

Throughout the presidential campaign, and particularly in recent days, Trump has highlighted his use of the "Merry Christmas" greeting, which he argues was neglected by his predecessor in favor of a more generic "happy holidays" greeting.

Obama supporters scoffed at this assertion, pointing out the many times he said "Merry Christmas" as president.

Despite Trump's emphasis on Christmas, the White House released a statement Tuesday from the president celebrating the first day of Kwanzaa, a week-long celebration of African heritage.

"Together, let us celebrate during this joyous time the richness of the past and look with hope toward a brighter future," the statement read. "As families and friends join to light the Kinara, Melania and I extend our warmest wishes for a joyful holiday season and a prosperous year to come."

It didn't take long for his critics to dig up a tweet from 2011, when then-reality star Trump mocked Obama for issuing a statement on Kwanzaa and linked to an article that called Kwanzaa a "fake holiday."

Earlier in the morning, Trump touted the tax cut bill he signed into law last week before leaving Washington for his holiday vacation. He took a jab at the individual mandate in the Affordable Care Act and promised to "develop a great new HealthCare plan" to replace it.

"Based on the fact that the very unfair and unpopular Individual Mandate has been terminated as part of our Tax Cut Bill, which essentially Repeals (over time) ObamaCare," Trump tweeted, "the Democrats & Republicans will eventually come together and develop a great new HealthCare plan!"