Washington - US Representative Elijah Cummings, one of the most influential Democrats in Congress and a key figure in the impeachment inquiry against President Donald Trump, died on Thursday at age 68.

The cause of death was “complications concerning longstanding health challenges,” his office said in a statement.

Cummings had been absent recently from Congress due to health concerns including heart and knee problems.

The son of sharecroppers who rose to lead the powerful House Oversight and Reform Committee, Cummings clashed with Trump over multiple probes involving the Republican president, from his personal finances to possible abuses at federal agencies.

The oversight committee is one of three congressional panels leading impeachment proceedings that were launched on Sept. 24 after Trump asked Ukraine to investigate 2020 Democratic presidential rival Joe Biden.

Cummings’ replacement as chairman will be decided in the coming days, largely by House Speaker Nancy Pelosi. Such replacements are often based on seniority, which would put Representative Carolyn Maloney of New York next in line, but it is not necessarily the deciding factor.

The Maryland Democrat, first elected in 1996, served as oversight chairman since January after the Democrats gained control of the House of Representatives in 2018 elections.

Before the impeachment probe, Cummings’ committee had been investigating whether Trump used his office to enrich himself, his family or his businesses including Trump hotels.

His panel has also been involved in fights with the Trump administration over subpoenas challenged by the president.

The African American lawmaker called Trump a racist and sharply criticised his immigration policies.