Watford have announced the signing of Italy international Marco Motta, subject to international clearance.
Mark Noble has signed a new deal with West Ham which will keep him at the club until the summer of 2020.
The 17-year-old, who has already won full international honours for Croatia, had been linked with a move to the Nou Camp and has now stated it will be his next destination.
Halilovic wrote on his Instagram account: "Thanks Dinamo Zagreb for everything!! My first club and biggest love!! Now is time to move on to Barcelona."
His current club have yet to comment on the claims of a deal being agreed, however reports in Croatia say Dinamo and Barcelona officials held talks in Zagreb on Thursday to negotiate the terms of Halilovic's release.
Croatian newspaper 24 Sata reported a deal was struck that will see Barcelona pay an initial fee of five million euros (£4.1million), to be followed by payments of two million euros (£1.6m) for every season that Halilovic makes 10 appearances for the Spanish club.