An international union representing millions of postal workers on Monday accused President Donald Trump’s administration of using the US postal service as a “pawn” in his election campaign.

The UNI Global Union voiced solidarity with postal unions in the United States, who have declared a day of action on Tuesday to #SavethePostOffice, following an onslaught of attacks from Trump that Democrats say threaten millions of mail-in ballots expected in November’s election.

“The United States Postal Service is being held hostage by a government intent on doing everything in its power to block postal voting in the run up to the election and undermine a trusted, necessary institution,” UNI chief Christy Hoffman said in a statement.

“The postal service, in the United States and globally, is a public good and a key function of government, not a pawn in an election campaign,” she added.

Americans are expected to vote by mail in massive numbers due to the coronavirus pandemic, but Trump has opposed more funding for the cash-strapped US Postal Service (USPS), even while acknowledging the money would be used to help process ballots.

Trump, who is trailing challenger Joe Biden in polls, also has repeatedly linked mail-in voting to electoral fraud.

The head of the USPS, Louis DeJoy, a Republican fundraiser who Trump appointed in May, has presided over the removal of mail collection boxes and processing equipment, and overseen a cut in overtime pay.

USPS has warned most states that it cannot guarantee on-time delivery of mail-in ballots.

The US House of Representatives passed a bill Saturday to give it a $25 billion boost, but it is expected to die in the Republican-led Senate.

USPS, which employs some 630,000 people, announced last week that it would hold off on operational changes until after the November 3 election.

But UNI, which represents more than 20 million workers worldwide including 2.5 million postal workers, said it remained “alarmed by recent attempts to weaken the USPS during the pandemic” and ahead of the elections.

It added that millions of Americans rely on postal services for prescription deliveries and social security payments.

“The intentional degrading of the post office is undermining the physical and financial health of Americans while attempting to strip people of their most basic right in a democracy,” Hoffman warned.