West Ham are expected to complete a double swoop for Germany striker Niclas Fullkrug and Argentina midfielder Guido Rodriguez early this week.
The Hammers have agreed a £27m fee with Borussia Dortmund for Fullkrug, 31, and have emerged as the preferred destination for free agent Rodriguez, 30.
Both players were due to fly to England at the weekend to undergo medical tests and sign their contracts with West Ham.
The deals follow the club’s signing of Dutch youngster Crysencio Summerville from Leeds United for £25m on Saturday.
He became their third major signing of the summer, after Wolves defender Max Kilman and 18-year-old Brazilian winger Luis Guilherme.
West Ham have backed new manager Julen Lopetegui in his first transfer window since succeeding David Moyes at the end of last season.
Late bloomer Fullkrug has 13 goals in 21 games for Germany and helped Dortmund to reach the Champions League final last term.
Rodriguez was out of contract after four years at Spanish side Real Betis. He previously played for Mexican teams Club AMerica and Tijuana as well as River Plate in his homeland.
West Ham have also been linked with a move for Manchester United’s former Crystal Palace defender Aaron Wan-Bissaka.