Family members say Laura Macintyre and Eilidh MacLeod haven't been heard from since the explosion.
Police Appeal Over Greenock Murder
Police have launched a murder inquiry following the post-mortem of a man found in a common close.
Stephen McGowan, 23, was found seriously injured in a close in Tobago Street, Greenock, in the early hours of yesterday morning.
Senior investigating officer DCI Jim Smith, from Police Scotland's major investigation team, said: £Mr McGowan was found in a common close in Tobago Street with serious injuries. He was pronounced dead at the scene.
"I am appealing for witnesses to come forward and assist us with this investigation.
"We have had an excellent response from the public so far, however I'm still keen to hear from anyone who may have been in the vicinity of the James Watt Wetherspoons Bar, Waterline Bar or Reds Nightclub that are in the Cathcart Street area of Greenock around 3.20am on Sunday morning.
"I am keen to confirm the last movements of Mr McGowan and again ask anyone who may have met or spoken with him in the early hours of Sunday July 27 2014 to get in touch through 101, or alternatively through Crimestoppers.''
The families of two girls from the Western Isles missing after attending the concert in Manchester targeted in a terror attack have issued appeals on social media.
Crews were called to the former Royal Victoria Hospital site this afternoon.
John Bermingham was also accused of assault and a breach of a Sexual Offences Prevention Order.
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