West Ham are in talks to sign four players from the Portuguese Primeira Liga, including internationals Moussa Marega and Yacine Brahimi.
The Hammers are in talks with Porto over a double deal for the Mali and Algeria internationals, while the club are also talking with Benfica over the signing over Joao Felix, and close to completing the signing of Vitoria Guimaraes forward Xande Silva.
A delegation from the Premier League club is currently in Portugal, not only to try and force these deals over the line but also to set up working partnerships with Porto and Benfica.
Mali international striker Marega and Algeria winger Brahimi are the most established of the quartet.
Marega, who was born in France, has been a prolific goalscorer since arriving in Portugal with Maritimo during the 2014-15 season.
Last season was his best, with 23 goals coming in 38 games for Porto - his first full campaign with the club he joined in January 2016.
Brahimi has been a regular in Porto's first team for the last four years and has scored 40 goals for the club from a predominately wide role.
Attacking midfielder Joao Felix has, until now, only featured for Benfica's B team but the 18-year-old is highly-rated and has been capped five times at U21 level by Portugal.
Borussia Dortmund and at least two other Premier League clubs are understood to have been interested in him.
Xande Silva has represented Portugal at all youth levels from U15 to U21 and Sky Sports News understands he is already in England ahead of a medical.