Donald Trump’s haphazard attempt to relaunch his communications operationafter six months as president will face its first test next week, when his son-in-law testifies about alleged links to Russia.

The appointment as communications director of Anthony Scaramucci, a financier with little experience but a feisty New York style that Trump admires, led to the resignation of press secretary Sean Spicer and suggested that White House messaging could take on an even more combative tone. On Saturday, Trump duly fired off 10 tweets on topics ranging from healthcare to old rival Hillary Clinton to the Russia investigations that continue to haunt him.

Adam Schiff, the ranking Democrat on the House intelligence committee, responded on the same medium: “Glad to see new communications director has things under control. The stream of consciousness strategy never fails, right?”

The president’s son-in-law and senior adviser Jared Kushner is due to speak behind closed doors with the Senate intelligence committee on Monday and House intelligence committee on Tuesday. Donald Trump Jr and former campaign chairman Paul Manafort are set to undergo private interviews with the Senate judiciary committee on a date yet to be determined.

Trump associates are also under investigation by special counsel Robert Mueller and Manafort – who bought three New York properties between 2006 and 2013, including one in Trump Tower in Manhattan – could be put under pressure to cooperate because of money laundering accusations against him, Reuters reported on Saturday, citing two unnamed sources.

Russia dominated the first half year of the Trump presidency and this week, billed as “Made in America week” to champion homegrown manufacturing, was no different. First it emerged that the president had a second, previously undisclosed meeting with Russia’s Vladimir Putin at the G20 meeting in Hamburg.

Then, in an extraordinary interview with the New York Times, Trump said he regretted hiring attorney general Jeff Sessions because Sessions in March recused himself from overseeing an investigation into Russian interference in the election. The president also insisted that the former FBI director would be crossing a line if he scrutinizes his personal business ties.

And on Friday the Washington Post reported that Sergey Kislyak, the Russian ambassador to the US, has said he discussed election-related issues with Sessions during the 2016 election. The Post cited anonymous US officials who described US intelligence intercepts of Kislyak’s descriptions of his meetings with Sessions, who was then a foreign policy adviser to Trump.

The president responded to the report on Twitter on Saturday. He did not defend Sessions, but he did appear to confirm that the Post had seen a genuine piece of intelligence.

“A new INTELLIGENCE LEAK from the Amazon Washington Post,this time against A.G. Jeff Sessions,” Trump wrote at 6.33am. “These illegal leaks, like [former FBI direcotr James] Comey’s, must stop!” Washington Post owner Jeff Bezos is the chief executive of Amazon.

There are growing fears that Trump is trying to engineer the dismissal of Mueller, which would be likely to trigger a huge political backlash. On Saturday, the president tweeted: “So many people are asking why isn’t the A.G. or Special Council [sic] looking at the many Hillary Clinton or Comey crimes. 33,000 e-mails deleted? ... What about all of the Clinton ties to Russia, including Podesta Company, Uranium deal, Russian Reset, big dollar speeches etc.”

After the Post and Times reported that Trump is looking for compromising information on Mueller’s team and contemplating pardons for associates, Matt Miller, a former Obama justice department official, tweeted: “Takeaway from the Post & NYT pieces is we are headed for certain crisis. Trump just will not, cannot allow this investigation to go forward.”

Trump tweeted on Saturday: “While all agree the U. S. President has the complete power to pardon, why think of that when only crime so far is LEAKS against us. FAKE NEWS.”

The president is also on potential collision course with Congress after Democrats announced on Saturday that a bipartisan group of House and Senate negotiators have agreed on sweeping sanctions to punish Russia for interfering in the 2016 election as well as its military aggression in Ukraine and Syria.

The White House had objected to a key section of the bill that would mandate a congressional review if Trump, whose warm relations with Putin appear out of step with US policy, attempted to ease or end the sanctions against Moscow.

Senate minority leader Chuck Schumer said: “Given the many transgressions of Russia, and President Trump’s seeming inability to deal with them, a strong sanctions bill such as the one Democrats and Republicans have just agreed to is essential.”

With the White House apparently spoiling for more fights, Trump’s staff shake-up was internally divisive. Scaramucci, nicknamed “Mooch”, reportedly had the support of Kushner, his wife Ivanka Trump and strategic communications director Hope Hicks, but was vehemently opposed by chief of staff Reince Priebus, chief strategist Steve Bannon and Spicer, who promptly resigned. That robbed the daily press briefing, which had become a must-watch reality TV show, of its biggest star.

In a valedictory interview on Fox News, Spicer, who had one of the shortest tenures of any White House press secretary, made the improbable claim: “We had a very successful Made in America week this week, garnering over millions of impressions.”

His successor, Sarah Huckabee Sanders, is the third White House female press secretary. The daughter of former Arkanas governor and presidential candidate Mike Huckabee, she is seen as less abrasive though equally unapologetic about defending the president’s every word and deed.

Scaramucci, meanwhile, was asked about the time in 2015 he called Trump “another hack politician”. He replied: “He brings it up every 15 seconds, OK? So, Mr President, if you’re listening, I personally apologise for the 50th time for saying that.”

On Saturday, Trump tweeted: “In all fairness to Anthony Scaramucci, he wanted to endorse me 1st, before the Republican Primaries started, but didn’t think I was running!”

Trump Jr and Manafort had been due to testify publicly on Wednesday but the top Republican and Democrat on the Senate judiciary committee now say the men are negotiating the terms of their appearances. Both men face questions about a meeting with a lawyer and other Russians in June 2016 that was described to Trump Jr in emails as part of a Russian government effort to help his father’s campaign.

Trump tweeted on Saturday: “My son Donald openly gave his e-mails to the media & authorities whereas Crooked Hillary Clinton deleted (& acid washed) her 33,000 e-mails!” Trump Jr only released his emails after becoming aware that the New York Times was in possession of them.

Meanwhile, the Russia investigations and discord at the White House continue to distract from Trump’s struggle to pass legislation despite Republicans controlling the Senate and House of Representatives. Senators remain deadlocked in their attempt to keep their promise to repeal and replace Barack Obama’s signature healthcare law.

The president, who has repeatedly shifted his stance, wrote on Saturday: “ObamaCare is dead and the Democrats are obstructionists, no ideas or votes, only obstruction. It is solely up to the 52 Republican Senators!”

The president then travelled to Naval Station Norfolk in Virginia, to place in commission the $12.9bn nuclear-powered aircraft carrier USS Gerald R Ford.

“American hands and American steel have constructed a 100,000-ton message to the world: American might is second to none,” he told an audience of thousands including former vice-president Dick Cheney and ex-defense secretary Donald Rumsfeld.

Wearing his usual dark suit, white shirt and red tie, the commander-in-chief promised to boost military spending but said the public could help by pressuring their members of Congress. He ad-libbed: “And by the way, you can also call those senators to make sure you get healthcare.”