Hundreds of journalists for Voice of America (VOA) - most of its remaining staff - have been fired by President Donald Trump's administration, effectively shutting down the US-funded news outlet.

The administration said the layoffs were because the agency was "riddled with dysfunction, bias and waste".

Steve Herman, VOA's chief national correspondent, called the dismantling of the outlet, which was set up during World War Two to counter Nazi propaganda, a "historic act of self-sabotage".

Among those axed were Persian-language reporters who had been on administrative leave, but were called back to work last week after Israel attacked Iran.

According to the Associated Press news agency, the Persian reporters had left the office on Friday for a cigarette break, and were not allowed to re-enter the building after the termination notices went out.

"Today, we took decisive action to effectuate President Trump's agenda to shrink the out-of-control federal bureaucracy," Kari Lake, whom the president appointed to run VOA, said in a statement on Friday announcing the layoffs of 639 employees.

In total, more than 85% of the agency's employees - about 1,400 staff - have lost their jobs since March.

She noted that 50 employees would remain employed across VOA, the Office of Cuba Broadcasting, and VOA's parent company, the US Agency for Global Media (USAGM).

A statement issued by three VOA journalists who have been suing to stop the elimination of the network said about the latest firings: "It spells the death of 83 years of independent journalism that upholds US ideals of democracy and freedom around the world."

The move had been expected since March when Trump ordered VOA, as well as USAGM, which oversees VOA and funds outlets such as Radio Free Europe and Radio Free Asia, to be "eliminated to the maximum extent consistent with applicable law".

The agencies have won acclaim and international recognition for their reporting in places where press freedom is severely curtailed or non-existent, from China and Cambodia to Russia and North Korea.

But Dan Robinson, a former VOA news correspondent, wrote in an op-ed last year that the outlet had become a "hubris-filled rogue operation often reflecting a leftist bias aligned with partisan national media".

Trump's criticisms of VOA come as part of his broader attacks against the US media, which studies suggest American news consumers view as highly polarised.

The president has also urged his fellow Republicans to remove federal funding for National Public Radio (NPR) and the Public Broadcasting Service (PBS).