Former Trump White House chief of staff Mark Meadows and other top aides subpoenaed by the House select committee investigating the Capitol attack are expected to defy orders for documents and testimony related to 6 January, according to a source familiar with the matter.

The move to defy the subpoenas would mark the first major investigative hurdle faced by the select committee and threatens to touch off an extended legal battle as the former president pushes some of his most senior aides to undercut the inquiry.

All four Trump aides targeted by the select committee – Meadows, deputy chief of staff Dan Scavino, strategist Steve Bannon and defense department aide Kash Patel – are expected to resist the orders because Trump is preparing to direct them to do so, the source said.

The select committee had issued the subpoenas under the threat of criminal prosecution in the event of non-compliance, warning that the penalty for defying a congressional subpoena would be far graver under the Biden administration than during the Trump presidency.

But increasingly concerned with the far-reaching nature of the 6 January investigation, Trump and his legal team, led by former deputy White House counsel Patrick Philbin, are moving to instruct the attorneys for the subpoenaed aides to defy the orders.

The basis for Trump’s pressing aides to not cooperate is being mounted on grounds of executive privilege, the source said, over claims that sensitive conversations about what he knew in advance of plans to stop the certification of Joe Biden’s election victory should remain secret.

Philbin appears less convinced than Trump about the strength of the legal argument, the sources said, in part because the justice department previously declined to assert the protection for 6 January testimony, suggesting it did not exist to protect Trump’s personal interests.

The former president’s lawyer, sources said, instead seems to view the strategy more as an effective way to slow-walk the select committee, which is aiming to produce a final report before the 2022 midterm elections, to keep the inquiry non-partisan.

It was not clear on Tuesday whether Trump would push aides to defy all elements of the subpoenas, the source cautioned – access to some emails or call records demanded by the select committee might be waived.

But Trump’s strategy mirrors the playbook he used to prevent House Democrats from deposing his top advisors during his presidency. Former White House counsel Don McGahn, for instance, only testified to congress about the Mueller inquiry once Trump left office.

House select committee investigators had demanded that the four Trump aides turn over emails, call records and other documents related to the Capitol attack by Thursday and then appear before the panel for closed-door depositions next week.

But with the former president expected to insist to Philbin that Meadows, Scavino, Bannon and Patel mount blanket refusals against the subpoenas, the sources said, the select committee at present appears likely to see none of the requests fulfilled.

The move means that House select committee investigators now face the key decision over how to enforce the orders – and whether they make a criminal referral to the justice department after the Thursday deadline for documents or next week’s crunch date for testimony.

House select committee chairman Bennie Thompson told reporters recently that he was prepared to pursue criminal referrals to witnesses who defied subpoenas and subpoena deadlines, as the panel escalates the pace of its evidence-gathering part of its investigation.

“We’ll do whatever the law allows us to do,” Thompson said last Friday on the subject of prosecuting recalcitrant witnesses. “For those who don’t agree to come in voluntarily, we’ll do criminal referrals.”

A spokesperson for the select committee declined to comment about how the panel intended to secure compliance.

The legal battle to force some of Trump’s most senior White House aides to comply with the subpoenas – however it is manifested – is likely to lead to constitutional clashes in court that would test the power of Congress’s oversight authority over the executive branch.

But members of the select committee in recent days have expressed quiet optimism at least about the potential prosecution of witnesses who might defy subpoenas, in part because of the Biden administration’s public support for the investigation.

The select committee said in the subpoena letters to Meadows, Bannon, Scavino and Patel that they were key persons of interest over what they knew about the extent of Trump’s involvement in the Capitol attack, which left five dead and more than 140 injured.

Meadows, the former White House chief of staff, remains of special interest to House select committee investigators since he was involved in efforts to subvert the results of the 2020 election and remained by Trump’s side as rioters stormed the Capitol in his name.

He was also in contact with Patel over at the defense department, the select committee asserted, and communicated with members of the Women for America First group that planned the ‘Stop the Steal’ rally that deteriorated into the 6 January insurrection.

Scavino, the former White House deputy chief of staff, became a person of interest after it emerged that he met with Trump the day before the Capitol attack to discuss how to persuade members of Congress not to certify the election, according to his subpoena letter.

The select committee said in the subpoena letter to Bannon that they wanted to hear from Trump’s former chief strategist, who was present at the Willard Hotel on 5 January to strategize with Trump campaign officials how to stop the election certification.

Patel, meanwhile, is under scrutiny since he was involved in Pentagon discussions about security at the Capitol before and after the riot. The select committee added they were also examining reports Trump tried to install him as deputy CIA director.