A rescue operation was stood down by the Coastguard on Friday night after almost five hours of searching when a tugboat with two people on board capsized in the River Clyde off Greenock.
HM Coastguard told the Record that the operation had been "handed over" to Police Scotland when their involvement came to an end at 8pm.
Police later confirmed they too had stepped down but would resume searching on Saturday morning.
Two people were on board the vessel when it capsized. It is unknown whether there have been any casualties.
Emergency search crews were called to a location just off Custom House Quay on the west coast on Friday, February 24, around 3.30pm.
The major operation also included Helensburgh RNLI lifeboat, several police launch boats and rescue crafts from vessels in the area who went to the scene when the alarm was raised.
Some witnesses to the emergency said they feared crew had become trapped when the boat capsized. Pictures from the scene showed what appeared to be the boat sinking while rescue teams assist.
An eyewitness said a number of first responders clambered aboard the upturned hull of the boat shortly before it sank.
They reportedly tapped on the hull trying to get a response from anyone inside as the vessel started to drift beneath the water. It is reported that "minutes later", the boat sank.
The tug boat, called the Biter, which is operated by Clyde Marine Services, was escorting the Hebridean Princess cruise ship into the harbour at about 3.30pm when it was apparently pulled over.
Police cordoned off the area near Custom House Quay in the Inverclyde town while the search continued into night fall.
A Coastguard spokesperson said: "HM Coastguard has been responding to reports of a capsized vessel off Custom House Quay in Greenock today, February 24.
"It is believed the vessel had two crew members onboard.
"Just before 3.30pm Coastguard Rescue Teams from Helensburgh and Greenock, a lifeboat from Helensburgh RNLI and the Coastguard helicopter from Prestwick were sent to assist and searched the area.
"Multiple vessels on the Clyde in the vicinity of the incident also responded, including an MOD Police vessel.
"The Coastguard's involvement in the surface search was terminated at 8pm."
A Police Scotland spokesperson said: “Police were made aware of a tugboat having capsized off Custom House Quay in Greenock around 3.30pm on Friday, 24 February, 2023.
“Emergency services attended, including HM Coastguard and RNLI.
“Officers, including Police Scotland’s Dive and Marine Unit and Air Support Unit, have been carrying out searches in the area and these searches will resume on the morning of Saturday, 25 February.
“Enquiries are ongoing, assisted by partners, to establish the full circumstances."
Clyde Marine Services have been contacted for comment.
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