WASHINGTON (Reuters) - Donald Trump, leading the pack for the Republican presidential nomination, has reached out to House of Representatives Speaker Paul Ryan, it was disclosed on Wednesday, even as some Republicans strategized over how to potentially knock the billionaire businessman’s campaign off its stride.

U.S. House Speaker Paul Ryan (R-WI) holds a weekly news conference at the U.S. Capitol in Washington January 7, 2016. REUTERS/Jonathan Ernst

The Trump campaign contacted Ryan’s office late on Monday, a spokeswoman for Ryan said, on the eve of the Super Tuesday nominating contests in which hundreds of delegates were at stake for the Republican candidates.

The Trump overture also came a day before the Republican speaker publicly admonished Trump over his failure to repudiate the backing of his candidacy by a white supremacist group. Trump responded with a warning to Ryan.

“We have heard from the (Trump) campaign, but the two have not yet spoken,” Ryan spokesman Brendan Buck said in a statement released on Twitter on Wednesday, one day after Trump swept victories in seven of the 11 states that held Republican nominating contests on the biggest day in the primary season.

Ryan spokeswoman AshLee Strong did not describe the subject or details of Trump’s overture to the speaker.

After months of shrugging off Trump’s candidacy, Republicans are now grappling with the distinct possibility that he may be their party’s nominee to take on the Democrats, likely led by Hillary Clinton, in the Nov. 8 presidential election.

A Republican senator who asked not to be identified, and a senior aide to another Republican senator, told Reuters that many private conversations were underway on Capitol Hill about finding ways to slow or stop Trump.

“People are leaning on people everywhere,” to convince Ohio Governor John Kasich to exit the race so the party can unify around a single Trump alternative, either Senator Marco Rubio or Senator Ted Cruz.

Kasich, however, was expected to stay in at least until the Ohio primary on March 15.

At the core of such conversations, said the aide and another senior Senate Republican aide, who also asked not to be identified, is avoiding a deadlock at the Republican convention, which “would forever result in the loss of our base,” said one of the aides.

Ryan has until this week avoided commenting on the presidential race. On Tuesday he said any Republican nominee must reject any group “built on bigotry.” The remark was aimed at Trump after Trump did not immediately repudiate support from a white supremacist group over the weekend.

Trump fired back at Ryan in a news conference in Florida on Tuesday night, warning the speaker would pay “a big price” if he stood in Trump’s way.

Ryan’s office did not say on Wednesday when the two men might talk. But Ryan’s spokesman said the speaker planned to be in touch with all of the Republican presidential candidates soon to discuss the conservative policy agenda.