London - Arsenal's move for Pierre-Emerick Aubameyang hinges on other transfers being agreed as Premier League clubs scramble to beat Wednesday's deadline.
The Borussia Dortmund striker is poised to make a €60 million switch to Arsenal, who are looking to bolster their forward options after the departure to Manchester United of Alexis Sanchez.
The BBC said Arsenal had agreed a fee with the Bundesliga club and personal terms with Gabon international Aubameyang, 28, but the German club will only sanction the move if they get a replacement.
Arsenal striker Olivier Giroud is reportedly a key cog in the transfer - either as a direct replacement for Aubameyang or as part of a three-way deal, with Giroud moving to Chelsea and Michy Batshuayi swapping Stamford Bridge for Dortmund.
Reports in Italy suggest a Chelsea bid for Roma's former Manchester City striker Edin Dzeko has been unsuccessful.
Elsewhere, Liverpool striker Daniel Sturridge, 28, left Anfield on a loan deal until the end of the season after slipping down the pecking order under Jurgen Klopp.
Barcelona winger Gerard Deulofeu has become Javi Gracia's first signing as Watford manager after arriving at Vicarage Road on loan until the end of the season.
Millwall re-signed veteran Australia international Tim Cahill, 14 years after he left the Den to join Everton.
"It's hard to put into words (what it feels like to wear a Millwall shirt again) - I'm still taking it in now," the 38-year-old told Millwall's website.
Celtic have signed Chelsea midfielder Charly Musonda on an 18-month contract, with left-back Baba Rahman departing Stamford Bridge for Schalke in a similar arrangement.
Meanwhile, Manchetser City have secure the services of Aymeric Laporte from Spanish club Athletic Bilbao.