"Those in the highest levels of the government must stop invoking fear," Elijah Cummings had said

Senior Democratic Congressman Elijah Cummings, who was at the center of the Trump impeachment inquiry, died early Thursday at the age of 68, US media reported.

The veteran Baltimore representative died at Johns Hopkins Hospital "due to complications concerning longstanding health challenges," reports said, quoting a statement from his office.

As chairman of the House Oversight and Reform Committee, Cummings was at the center of the impeachment inquiry into President Donald Trump and had clashed with him.

In July, the president described Baltimore as a "rat and rodent infested mess" unfit for humans and blamed it on Cummings, an African-American Democrat who has represented much of the majority-black city in Congress since 1996.

Cummings did not directly respond to Trump, but said government officials must stop making "hateful, incendiary comments" that only divide the nation and distract from its real problems.

"Those in the highest levels of the government must stop invoking fear, using racist language and encouraging reprehensible behavior," Cummings said in an August speech at the National Press Club.

"It only creates more division among us and severely limits our ability to work together for the common good."

"As a country we finally must say that enough is enough, that we are done with the hateful rhetoric, that we are done with the mass shootings, that we are done with the white supremacists who are terrorizing our country and fighting against everything our country stands for and everything our phenomenal military has fought for," he added.

The Baltimore Sun said Cummings was "known for his devotion to Baltimore and civil rights, and for blunt and passionate speechmaking."

It said he had particularly resented Trump's tweet that four Congresswomen of color should "go back" to their countries.

Cummings had also clashed with the president over the detention of immigrants.

He was born in 1951, one of seven children to a couple who were sharecroppers.