Police investigating the disappearance of Madeleine McCann have started searching a reservoir in Portugal.
On Monday, officials announced a fresh search would be carried out in a major development.
Police divers were seen entering the water early on Tuesday morning at the Barragem do Arade reservoir, while a police motor boat has also been sent into the water with two officers onboard.
Tents have been erected on the banks of the reservoir and officers from Portugal, Germany and the UK were seen holding morning briefings on Tuesday, the BBC reported.
The reservoir is 50km from where three-year-old Madeleine disappeared in the holiday resort of Praia da Luz on 3 May 2007.
Investigators believe the prime suspect in her disappearance, convicted sex offender Christian Brueckner, 45, spent time in the area between 2000 and 2017.
Watch: Police investigating Madeleine McCann disappearance to search reservoir
German police believe he killed Madeleine, from Rothley, Leicestershire, after abducting her from a holiday apartment.
Yahoo News UK takes a look at who is involved in the search for Madeleine.
About a dozen officers with sniffer dogs were moving along the bank of the reservoir as part of the search.
A rigid-hull inflatable boat could be seen on the water as divers worked in the reservoir itself.
Two blue tents have been put up in one location, while the area that appears to be central to the search is about a mile away.
A statement issued on Monday evening by the Policia Judiciaria confirmed that it is co-ordinating searches of the area close to the Barragem do Arade reservoir.
It said: "The Policia Judiciaria confirms that, regarding the investigation into the disappearance of an English child, which occurred in the Algarve in 2007, steps are still being taken to fully clarify the situation.
"Within the scope of international co-operation, in the next few days in the Algarve region, new searches will be carried out."
Portuguese officers were pictured on Monday walking along dry tracks near the reservoir and sealing off areas with police tape.
Brueckner was identified as a suspect by Portuguese police in June 2020, and made an “arguido”, a formal suspect, in April 2022.
It is not the first time the reservoir has been searched.
In 2008, Portuguese lawyer Marcos Aragao Correia paid for specialist divers to check the waterway after he claimed to have been tipped off by criminal contacts that Madeleine’s body was in the reservoir.
The new search of the area near the reservoir has been requested by German police, who believe Brueckner visited the area saying he called it his "little paradise".
He denies any involvement in her disappearance.
Brueckner is in prison in Germany for the rape of a 72-year-old woman in 2005 in the same area where Madeleine went missing.
He is facing charges in Germany over a number of separate sex offences allegedly committed in Portugal during that time.
He was charged in October 2022 with three counts of rape and two charges of child sex abuse, unrelated to Madeleine’s disappearance.
A brief statement from the prosecutor’s office in the German city of Braunschweig confirmed the search but did not reveal why it was taking place.
British officers will also be present, the Policia Judiciaria said, in a sign that their heavy involvement since Madeleine went missing will continue.
The most recent search in Portugal in relation to Madeleine's disappearance was in 2014 when British police were given permission to examine scrubland near where she vanished.
In 2011, Scotland Yard launched a review of the case after a request from then home secretary Theresa May.
The following year, its detectives said they believed Madeleine could still be alive and released an age-progression image of how she might look as a nine-year-old. British police called on Portuguese authorities to reopen the case, but their counterparts said they had found no new material.
In 2013, Scotland Yard confirmed it had launched its own investigation, Operation Grange, into Madeleine’s disappearance, saying it had “genuinely new” lines of inquiry. Later that year, Portuguese police reopen the case.
In June 2014, British police used sniffer dogs and specialist teams to search an area of scrubland close to where Madeleine went missing.