WASHINGTON — Sen. Rand Paul, one of the few Republicans who has defended President Donald Trump’s outreach to Russia, has gone even further to solidify ties: During a trip to Moscow he announced that he’d delivered a letter from Trump to Russian President Vladimir Putin’s administration.

Paul boasted via Twitter Wednesday morning that he was “honored” to deliver the missive, which he said “emphasized the importance of further engagement in various areas including countering terrorism, enhancing legislative dialogue and resuming cultural exchanges.”

The tweet set off a flurry of speculation, given the controversy sparked by a Trump-Putin summit in Helsinki last month. Yet the White House said after Paul’s declaration that it was the Kentucky senator who had requested the letter to Putin — and that Trump included in the letter issues that Paul has raised.

“At Senator Paul’s request, President Trump provided a letter of introduction,” deputy press secretary Hogan Gidley said, adding that Trump in the letter “mentioned topics of interest that Senator Paul wanted to discuss with President Putin.”

Paul is on a trip to Russia this week he has said is aimed at boosting engagement with the U.S. adversary. The Russian news agency Tass quoted Kremlin spokesman Dmitry Peskov as saying the Trump letter to Putin had been delivered to the Russian side “through diplomatic channels, but the Kremlin has not familiarized itself with the letter as of yet.”

The letter comes three weeks after Trump met with Putin in Helsinki, Finland, sparking a backlash in both parties after his initial refusal to side with the U.S. intelligence community over Russian denials about meddling in the 2016 presidential election.

And the letter came the same day the State Department announced it would impose new sanctions on Russia after determining its government had used chemical or biological weapons in violation of international law in the nerve agent poisoning of former spy Sergei Skripal and his daughter, Yulia.

Paul has proven to be one of the few allies for Trump on Russia, calling the criticism directed at Trump’s performance in Helsinki a reflection of “how unhinged people are in their hatred for the president.” On the Senate floor, Paul objected to a resolution expressing support for the intelligence community, as well as special counsel Robert Mueller’s investigation, calling it a sign of “Trump derangement syndrome.”

Paul, a member of the Senate Foreign Relations Committee, later announced his own trip to Russia, saying that he hoped to better relations between the two countries. Earlier this week Paul announced that he had secured an agreement with his Russian counterparts for Russian legislators to visit the U.S. and “continue dialogue on vital issues such as nuclear non-proliferation and combating terrorism.”

Texas Republican Sen. Don Huffines, who chaired Paul’s 2016 presidential campaign in Texas, was along on the trip, financed by the Cato Institute, a Washington, D.C.-based libertarian think tank.

Huffines said via Twitter that he was “pressing Russian officials on election integrity & relaying my constituents’ concerns. My message to the Russians: ‘Don’t mess with Texas elections!’”

Paul was an enthusiastic supporter of Trump’s decision to meet with Putin in the first place, writing that “dialogue is especially important when hundreds of millions of lives are at stake, as is the case in relations between the United States and nuclear-armed Russia.”

The two have bonded over Russia, even after they savaged each other on the 2016 presidential primary campaign trail, with Paul at one point deriding Trump as an “orange-faced windbag” and the president retorting that Paul was “truly weird.”

Paul is the ninth Republican member of Congress to travel to Russia this summer. A contingent of eight Republicans spent Fourth of July in Moscow ahead of Trump’s meeting with Putin, but returned to face a public backlash that they had failed to press Russia on its interference in the 2016 election. One Russian official called the July meeting with the lawmakers one of the easiest of his life.

Trump soon after his summit with Putin had invited the Russian president to Washington this fall, but Trump’s national security adviser, John Bolton, later said any meeting would be put off until 2019.