Inter signs Kuzmanovic and Schelotto
Inter also completed deals for Zdravko Kuzmanovic and Ezequiel Schelotto - who have both already trained with their new teammates - and signed Lazio goalkeeper Juan Pablo Carrizo on loan.
Schelotto moves from Atalanta, where the winger's form earned him a debut Italy appearance in the friendly against England in August.
''To be here is a dream come true,'' the 23-year-old Schelotto said. ''Atalanta will always be in my heart, but now I'm hoping to get to the Champions League with Inter and to convince (Italy coach Cesare) Prandelli to call me up again.''
Kuzmanovic, a Serbia midfielder, is signing from Stuttgart.
Kovacic had to drive 400 kilometers (250 miles) to take a flight to Milan on Wednesday night after Inter reached an agreement with Dinamo Zagreb for the 18-year-old midfielder.
''Everything happened really fast,'' Kovacic said, who had been with his former teammates in Bosnia. ''I was training with Dinamo and my coach came to tell me I would be playing for Inter. I replied, `Are you serious?' For me it's a dream and now I can't really explain how I feel.
''I am really happy to be here because Inter is a great club and I will give my maximum.''
Atalanta was also busy, bringing in Franco Brienza, Matteo Contini and Cristiano Del Grosso to take their tally for signings this month to eight.
AC Milan, which pulled off the biggest coup of the transfer window by adding Mario Balotelli, has signed defender Bartosz Salamon from Brescia until 2017.
''I am very happy to sign for Milan,'' he said. ''I am not afraid of anything.''
Napoli beat Premier League club Queens Park Rangers to the signing of FC Porto defender Rolando on loan, while former Juventus midfielder Mohamed Sissoko returned to Italy, joining Fiorentina on loan from Paris Saint-Germain.
Earlier, Cagliari made its first move of the transfer window, signing Uruguayan midfielder Matias Cabrera on a 3 1/2-year deal.