COLOMBO/MALE (Reuters) - Maldives accused the United States of intimidation on Friday, a day after Washington called for the release of “falsely accused” political prisoners and threatened action if the island’s upcoming election is not free and fair.

Maldives is due to hold a presidential election on Sept. 23 when incumbent Abdulla Yameen will seek a second five-year term.

Heather Nauert, a spokeswoman at the U.S. State Department, said in a statement released on Thursday that the United States was concerned about continued “democratic backsliding in Maldives” ahead of the vote.

“We join the international community in calling for the release of falsely accused political prisoners; full implementation of the Maldivian Supreme Court’s February ruling overturning the convictions of opposition members; an end to executive interference in the Parliament and judiciary ...” Nauert said.

“Absent Maldives’ return to a democratic path, the United States will consider appropriate measures against those individuals who undermine democracy, the rule of law, and a free and fair electoral process,” she said.

The Maldives’ foreign ministry said on Friday that the United States’ call for the release of ‘falsely accused political prisoners’ was seen as “an act of intimidation” and imposing undue influence on the democratic processes of a sovereign state before a key poll.

It urged the United States to allow the Maldivians to freely decide who should lead them on Sept. 23 for the next five years.

“It should be noted that the Maldives has no political prisoners, and all those who have been convicted have undergone due process,” it said in a statement.

The Indian Ocean tourist island has been beset by political instability since a police mutiny forced its first democratically elected leader, Mohamed Nasheed, to quit in 2012.

President Yameen imposed a state of emergency earlier this year, since lifted, to annul a Feb. 1 Supreme Court ruling that quashed convictions against nine opposition leaders and that ordered his government to free those held in prison.

His government has rejected repeated requests by the United Nations, rights groups, and the West to release the president’s rivals and follow fair legal procedures.

The European Union in July warned of possible sanctions ranging from travel bans to asset freezes against those in the Maldives responsible for human rights violations and undermining the rule of law.

In the election, Yameen will be challenged by veteran lawmaker Ibrahim “Ibu” Mohamed Solih representing the opposition Democratic Party after former president Nasheed, who now lives in exile in Sri Lanka, withdrew as a candidate after the national election commission ruled him ineligible to run.