Republican members of Congress have joined state party officials in calling for the New York representative George Santos to resign, heaping more pressure on the disgraced politician who won election in November with a largely fictional biography.

Anthony D’Esposito, who represents New York’s fourth congressional district, neighbouring Santos in the third, said on Wednesday Santos had lost the faith of voters and did “not have the ability” to represent them, the New York Times reported.

Santos, whose lies about his family background, education and work history were exposed by the Times, has insisted he will not resign, despite a slew of investigations and a complaint to the Federal Election Committee over his campaign finances.

D’Esposito told reporters he would actively encourage “other representatives in the House of Representatives to join me in rejecting” Santos.

He was joined in short order by three other first-term Republican congressmen from New York, the Times said. Two more weighed in on Thursday.

The three were Nick LaLota, who like Santos and D’Esposito represents parts of Long Island; Nick Langworthy, the New York party chair who represents part of the upstate southern tier; and Brandon Williams, from a district near Syracuse.

LaLota was particularly scathing, according to Axios.

“I definitely share their sentiments,” he said of state party officials’ calls for Santos to give up his seat. “What he’s done is disgraceful, dishonorable and unworthy of the office. I think he should resign.”

Williams tweeted a statement.

“As more revelations become public, I concur with the Nassau Republicans’ decision to request George Santos’ resignation,” he wrote.

“The constituents in NY-3 elected Representative Santos in part due to his biographical exaggerations and apparent deceptions. He must resign.”

On Thursday morning, CNN’s chief congressional reporter, Manu Raju, tweeted that he had spoken with two more Republican New Yorkers, Marcus Molinaro and Mike Lawler, who concurred with their fellow congressmen.

“There’s no way I believe [Santos] can fully fulfill his responsibilities,” Molinaro was quoted as saying.

Santos has admitted “embellishing” his résumé, including lying about his college record – he did not attend Baruch and New York University – and saying a “poor choice of words” created the impression he worked for Citigroup and Goldman Sachs.

He has claimed a tragic link to the Pulse nightclub shooting and said the attacks on New York on 11 September 2001 “claimed my mother’s life”. His mother died in 2016.

He has claimed to have Jewish roots and to be descended from Holocaust survivors. He has claimed to be part Black, but while voting for Kevin McCarthy to be House speaker last week, he appeared to flash a “white power” sign.

He is under investigation in New York and in Brazil, in the latter case over the use of a stolen checkbook.

On Thursday, Hakeem Jeffries, the Democratic minority leader in the House and another New Yorker, had stern words for Republican leaders.

Santos, Jeffries said, was “a complete and total fraud. He lied to the voters of the third congressional district in New York. He deceived and connived his way into Congress, and is now the responsibility of House Republicans to do something about it.

“This is not a partisan issue, but it is an issue that Republicans need to handle. Clean up your house. You can start with George Santos.”

Earlier this week, two New York Democrats, Daniel Goldman and Ritchie Torres, hand-delivered to Santos their request for an investigation of his campaign finances.

Jeffries said: “I was well aware of their decision to do so. But any matters before the ethics committee … should be resolved by members of the ethics committee.”

Kevin McCarthy, the Republican House speaker, was also asked about Santos on Thursday. He told reporters: “What I find is that voters have elected George Santos. If there is a concern he will go through ethics. If there is something that is found it will be dealt with in that manner. But they [voters] have a voice in this process.”

Santos remains defiant – even after being disowned by his own district Republican party.

On Wednesday, Joseph Cairo, chair of the Nassau county Republican committee, criticized Santos for running a campaign of “deceit, lies and fabrication”.

“He’s disgraced the House of Representatives, and we do not consider him one of our congresspeople,” Cairo told reporters. “Today, on behalf of the Nassau county Republican committee, I am calling for his immediate resignation.”

Cairo even said Santos did not just claim to have attended colleges he did not attend, but claimed to have been “a star on the Baruch volleyball team and that they won the league championship”.

In response, Santos tweeted: “I was elected to serve the people of the New York third district not the party and politicians, I remain committed to doing that and regret to hear that local officials refuse to work with my office to deliver results to keep our community safe and lower the cost of living.

“I will NOT resign!”