Former US President Donald Trump said on Friday he would vote no on an amendment which seeks to end Florida's six-week abortion ban. This comes a day after he seemed to indicate he would vote for the measure.

In an earlier interview with NBC, Trump said, "I am going to be voting that we need more than six weeks."

However his campaign quickly issued a statement saying that Trump had "simply reiterated that he believes six weeks is too short," and hadn't said how he would vote.

The Republican presidential candidate then appeared in an interview with Fox News Channel, clarifying his stance.

"I think six weeks, you need more time," he said. "At the same time, the Democrats are radical," he had added, repeating false claims around late-term abortions. "So I'll be voting no for that reason."

The initial confusion had drawn backlash from anti-abortion groups, several of which support and donate towards Trump's campaign for the November 5 presidential election.

In April he briefly considered supporting a possible nationwide 15-week ban but went on to say that states should set their own regulations.

What is the amendment?

Florida's upcoming ballot measure aims to legalize abortion until fetal viability.

That is a term healthcare providers use to describe if the pregnancy will continue to develop normally or not. This is generally assessed around the 24-week (6 months) mark.

The state currently has a ban on abortion after six weeks.

Democratic presidential nominee and Vice President Kamala Harris was quick to respond to Trump's stance.

"Donald Trump just made his position on abortion very clear: He will vote to uphold an abortion ban so extreme it applies before many women even know they are pregnant," she said in a statement.

Abortion rights has become a key issue in the US in the runup to elections, two years after the Supreme Court overturned the 1973 Roe v. Wade decision which ensured a constitutional right to abortion.

According to Reuters poll surveying young women published Thursday, Harris led Trump by 49% to 36% — a wider margin than seen in July.