Thai police have said there is "concrete" evidence against two Burmese men accused of killing Hannah Witheridge and David Miller, adding that the suspects' confessions stand.

The British tourists were found bludgeoned to death on the island of Koh Tao last month.

Mr Miller, from Jersey, died from drowning and a blow to the head, while Miss Witheridge, from Great Yarmouth, died from head wounds.

The two bar workers, named as Zaw Lin and Win Zaw Htun, have been charged with conspiracy to murder, conspiracy to rape and robbery over the attack.

Reports emerged earlier this week that a Burmese embassy official had formally retracted their confessions amid allegations the pair had been tortured.

But a spokesman for the Royal Thai Police strongly denied claims of torture and suggestions the confessions had been withdrawn.

Deputy police chief spokesman Colonel Kissana Phathanacharoen said: "We had them checked by a doctor before and after the inquiry because we thought the accused may claim they were tortured. The accused persons can say anything want.

"They can withdraw their confessions if they like. We have concrete evidence including DNA evidence from Hannah's body which matched the two suspects."

Thai police have been under domestic political pressure to solve the case, amid criticism over the investigation.

Amnesty International has called for an investigation into the torture allegations. The charity cited a lawyer from the Burmese embassy legal team who said he had been told police had beaten the suspect and "threatened him with electrocution".

The Foreign and Commonwealth Office has said it is concerned about the reports and expects a fair investigation.