Newcastle have signed Argentine duo Santiago Grondona and Mateo Carreras from the Jaguares Super Rugby team.
Grondona, a 22-year-old flanker, has won four caps for the Pumas and was part of the 23 that beat New Zealand in last month's Rugby Championship.
Winger Carreras, 20, has played for his country's sevens team and is the younger brother of recent Gloucester recruit Santiago Carreras.
Both players have agreed deals until the end of the current season.
They follow Argentina centre Matias Orlando, who joined Dean Richards' side earlier this year.
"Santiago and Mateo are both quality players who will further add to the competition we have within the squad," director of rugby Richards told the club website.
"Santiago is a very powerful player who at 6ft 6in (1.98m) can make a real physical impact, and Mateo has plenty of pace and footwork out wide.
"It's going to be all hands to the pump with key games coming thick and fast, and the opportunity to add two talented players like this was too good to pass up."