Washington, Sep 24: The US House select committee investigating the Jan 6 Capitol riot issued the first batch of subpoenas against four allies of former President Donald Trump, asking them to appear before it for depositions.

The subpoenas were sent to former top White House adviser Steve Bannon, former White House Chief of Staff Mark Meadows, former White House Deputy Chief of Staff Dan Scavino, and former Pentagon Chief of Staff Kash Patel, Xinhua news agency reported.

They were asked to produce documents related to the riot no later than October 7, and appear for depositions in the following week.

"The Committee is investigating the facts, circumstances, and causes of the January 6 attack and issues relating to the peaceful transfer of power, to identify and evaluate lessons learned and to recommend corrective laws, policies, procedures rules, or regulations," read a statement issued by Democratic Congressman of Mississippi Bennie Thompson, who serves as Chairman of the select committee.

In separate letters sent to each of the four former officials, the committee asked them to provide information on their involvement either in the lead-up to or in the aftermath of the riot.

House Intelligence Chairman Adam Schiff, a key member of the select committee, has warned that those who defy the subpoenas could face charges of criminal contempt.

Republicans have claimed that the select committee, whose members are mostly Democrats, is nothing but a tool for Democrats to gain partisan interests.

Some 140 police officers were reportedly injured when confronting Trump's supporters who breached the Capitol on January 6 in an attempt to stop Congress from certifying the results of the 2020 presidential election.

The Capitol riot left five dead, including a Capitol Police officer.

Four officers who responded to the riot reportedly died by suicide within seven months.

Trump was impeached by the Democrat-led House on one article of inciting insurrection on January 13 before being acquitted by the Senate.

He was the first-ever sitting American President to have been impeached and tried twice.

4 Trump allies subpoenaed over US Capitol riot