World Rugby said Monday it will seek explanations why a Romanian referee was chosen to officiate Belgium's World Cup qualifying win over Spain that put Romania into next year's World Cup.
At the end of their 18-10 loss in Brussels, Spanish players pursued referee Vlad Iordachescu, who had to be escorted off the pitch.
Victory would have seen Spain qualify for just a second World Cup in their history.
Instead, Romania qualified directly for the showpiece in Japan, while Spain have to win two playoffs, first against Portugal, and then a two-legged tie with Samoa if they are to qualify.
The Spanish Rugby Federation said on Sunday that they had lodged a formal complaint to Rugby Europe and World Rugby.
"While World Rugby does not appoint match officials for the Rugby Europe Championship, it is in contact with Rugby Europe to understand the context of events relating to the Belgium v Spain match in Brussels on Sunday, which doubled as an important RWC 2019 qualifier," World Rugby said in a statement.
Rugby Europe said it will wait for a supervisor's report on the match before taking any further action.
"Rugby Europe Selection Committee is waiting for the assessment report of the Supervisor for Belgium v Spain Match officials," read a Rugby Europe statement.
"In addition, this Committee will meet in Poznan next Friday on the occasion of the Rugby Europe U18 Championships. Its agenda will be modified and a large portion of the meeting will be devoted to the analysis of every stage of the Belgium v Spain game.
"Following this meeting, a statement will be released to Rugby Europe Board of Directors for dissemination."
In the immediate aftermath of the match, president of the Spanish Rugby Federation Alfonso Feijoo pinned responsibility for the defeat on the referee.
"Everyone who has seen the game will judge the referee," he told Spanish radio station Cadena SER. "He gave 10 penalties against us, the result comes from that."
However, on the team's return to Spain on Monday, Spain captain Jaime Nava apologised for his side's aggressive reaction towards the official at full-time.
"The persecution of the referee is very unfortunate and, as captain of the team, I want to apologise and say that doesn't correspond to the values of the sport, nor the identity of this team."