President Donald Trump and his legal team are planning to use the one-year anniversary this week of Robert Mueller's appointment to ratchet up pressure on the special counsel to close his investigation.

Trump and his lawyers are trying to set up the milestone on Thursday as a turning point in their campaign to end Mueller's probe into Russian election meddling and obstruction of justice, Rudy Giuliani, Trump's personal lawyer, said Tuesday in an interview. While he isn't threatening specific actions, Giuliani said they haven't ruled out additional steps if Mueller doesn't heed their calls.

"We are going to try as best we can to put the message out there that it has been a year, there has been no evidence presented of collusion or obstruction, and it is about time for them to end the investigation," Giuliani said. "We don't want to signal our action if this doesn't work — we are going to hope they listen to us — but obviously we have a Plan B and C."

Mueller was appointed as special counsel on May 17, 2017, eight days after Trump fired FBI Director James Comey. Trump's lawyers have been negotiating over a possible interview of Trump by Mueller's team for several months, as the president has been growing increasingly impatient.

Giuliani said he doesn't believe Mueller needs to interview Trump for the investigation to end and fears it would put Trump in unnecessary legal jeopardy.

Before Trump could agree to an interview, Giuliani said Mueller would need to show why one is needed given the 1.2 million pages of documents that have been turned over and dozens of White House staff who have been interviewed. Giuliani said he also wants assurances that the investigation would wrap up shortly after any such encounter.

"It is hard to recommend an interview when the questions presented indicate they have no evidence, and it is hard not to get at least the appearance they are attempting to trap him into perjury," Giuliani said.

There have been no back-and-forth conversations in the past two weeks between Giuliani and Mueller's team about the terms of an interview. Mueller had suggested to Trump's former lawyer John Dowd that he might issue a subpoena if Trump didn't agree to a voluntary interview.

Trump has been escalating his attacks on Mueller and his team since March after months of restraint at the urging of White House lawyer Ty Cobb, who announced his departure earlier this month. Trump called the investigation a "$10,000,000 Russian Witch Hunt" in a Twitter post Tuesday and last week called Mueller's team of lawyers "13 Angry Democrats." Mueller is a registered Republican.

Patience Gone

Cobb had argued that the quickest way for Trump to resolve the investigation would be to cooperate. In August, Cobb had assured Trump the investigation would be completed by the end of 2017. Now, almost halfway through 2018, Trump's patience has worn out, said a person close to the president. Adding to his frustration was last month's FBI raid on the home and office of his longtime lawyer Michael Cohen.

Mueller's probe includes looking into allegations that Trump asked Comey to end the investigation into his former national security adviser, Michael Flynn.

Mueller's appointment gave him broad authority to investigate Trump and his campaign, as well as any other issues that would arise out of the investigation. The probe has resulted in plea deals from Flynn, former Trump campaign adviser George Papadopoulos and Trump campaign aide Rick Gates. Former Trump campaign manager Paul Manafort was indicted on charges including money laundering. Mueller has also brought indictments against 13 Russian nationals on conspiracy charges.