Police carried out new searches at a reservoir in Portugal on Tuesday connected to the disappearance of British toddler Madeleine McCann, who vanished from a resort in the Algarve region 16 years ago.

AFP reporters on the scene of the remote Arade reservoir, around 50 kilometers (30 miles) from the Praia da Luz resort, saw police officers searching the bank along the dam with the help of a sniffer dog.

Two officers searched the water on board a fire department boat.

German prosecutors confirmed the search was taking place but said they could not give further details "for tactical investigative reasons".

Portuguese police had announced on Monday evening that new searches would be carried out "in the next few days, at the request of the German authorities" and "in the presence of the English authorities".

The steps were being taken with a view to "a total clarification of the situation", the police said in a statement.

German police are assisting the Portuguese authorities, the German prosecutors said, while London's Metropolitan Police said it also had officers on the ground.

Madeleine McCann was three years old when she went missing from her family's holiday apartment in Praia da Luz in 2007 while her parents dined at a nearby tapas bar.

Despite a huge international manhunt, no trace of her has been found and no one has been charged over her disappearance.

- 'Concrete evidence' -

German prosecutors revealed in June 2020 that they were investigating a German man, Christian Brueckner, in connection with the case, saying they had "concrete evidence" he killed Madeleine.

According to police, Brueckner lived in the Algarve region between 1995 and 2007, making a living doing odd jobs as well as burgling hotel rooms and holiday apartments.

Portuguese weekly magazine Expresso has reported that he would regularly spend time near the reservoir outside the small inland town of Silves.

Police already combed the site in 2008 but divers found only animal remains, according to media reports.

The area being searched was cordoned off on Tuesday and police had set up blue and white tents by the mass of water, set among wooded hills.

Police were monitoring access to the trails surrounding the Arade dam, built in the 1950s to irrigate agricultural land in the region.

"Sixteen years later, I very much doubt that they will find anything," Andre Calado, 25, who works in a hotel in a small village near the dam, told AFP.

- 'Still looking' -

The new search is the latest in a string of dramatic twists and turns in the McCann case, one of the highest-profile unsolved crime mysteries of recent years.

Portuguese police shelved 14 months of investigations in 2008 after controversially saying Maddie's parents were suspects before clearing them of any involvement. The case was reopened five years later citing "new elements".

After spending two years studying the case, British authorities opened their own investigation in 2013, before Germany named Brueckner as a suspect in 2020, then aged 43.

Brueckner, who Portuguese police also named as a formal suspect last year, is currently in jail in Germany for the 2005 rape of a 72-year-old American in Praia da Luz.

He was also charged last year with three counts of rape and two sexual offenses against children in Portugal between 2000 and 2017.

However, German prosecutors have yet to charge him over Madeleine's disappearance.

Madeleine's parents, Kate and Gerry McCann, said earlier this month they were "still looking" for their daughter in a message to mark her 20th birthday.

"Happy birthday Madeleine. Still missing. Still very much missed. Still looking. For as long as it takes," they said in a post on the official Facebook page of the Find Madeleine Campaign.

"We love you and we're waiting for you. We're never going to give up," they added in the message accompanied by a YouTube video with photos of the missing girl.

In early May, Madeleine's family held a vigil to mark 16 years since her disappearance.