Washington (AFP) - Former Green Party presidential candidate Jill Stein switched tactics in her campaign to force a recount in Pennsylvania, one of three battleground states won by Donald Trump where she has challenged the results.

The party dropped a bid to pursue the recount in a state court, citing difficulties raising a million dollar bond demanded by the tribunal. It said it would instead press on in federal court and file suit Monday.

That was also Stein's deadline for raising the bond money.

"Make no mistake -— the Stein campaign will continue to fight for a statewide recount in Pennsylvania," attorney Jonathan Abady said in a statement.

"Over the past several days, it has become clear that the barriers to verifying the vote in Pennsylvania are so pervasive and that the state court system is so ill-equipped to address this problem that we must seek federal court intervention," Abady said.

"Petitioners are regular citizens of ordinary means. They cannot afford to post the $1,000,000 bond required by the court," read a filing submitted earlier in the Commonwealth Court of Pennsylvania, announcing the state court drive was being dropped.

Stein plans to hold a rally on Monday across the street from Trump Tower in New York "vowing to fight tooth and nail to verify the accuracy, security and fairness of the vote," a statement read.

On Twitter, she added: "How odd is it that we must jump through bureaucratic hoops and raise millions of dollars so we can trust our election results? #Recount2016.

"#Recount2016 is so expensive because of elected leaders who have refused to invest in a 21st-century voting system," she said.

Stein's fundraising efforts for recounts in Pennsylvania, Michigan and Wisconsin have brought in nearly $7 million so far, according to her website. In all three traditionally Democratic-leaning states, Trump only narrowly defeated Democratic candidate Hillary Clinton.

Her recount request in Pennsylvania was complicated by opposition from Trump. Michigan's attorney general filed suit to halt Stein's recounts efforts in that state. And in Wisconsin, Trump supporters tried to stop the recount but it is underway.

Story continues

Stein's campaign has cited unspecified "anomalies" as grounds to mount a challenge in all three Rust Belt states.

The move came amid stepped-up calls from some of the president-elect's leftist opponents to challenge the results of the November 8 election, which followed a bitter campaign that included persistent charges of Russian hacking and allegations by Trump of fraud.

Although experts say there is virtually no chance of overturning the result, the demands could reignite debate over the legitimacy of Trump's election, already fueled by Clinton's lead in the popular vote which now stands at around 2.5 million.

Trump has stated without offering evidence that "millions" of people voted illegally and that were it not for this he would have won the popular vote as well.