Nicola Sturgeon is to hold talks with European Commission president Jean-Claude Juncker in Brussels today as she attempts to keep Scotland in the European Union.
The First Minister is also expected to meet European Parliament president Martin Schulz and Guy Verhofstadt, the former Belgian prime minister and leader of the Liberal group at the European Parliament.
It is understood European Council president Donald Tusk has no plans to meet Sturgeon because he does not consider it to be the right time.
The meeting with Schulz is expected to be the most high profile of the First Minster's meetings but Margaritis Schinas, chief spokesman for Mr Juncker, tweeted on Wednesday morning:
The First Minister's visit comes after MSPs voted to give her a "mandate" to hold discussions with EU institutions, as well as the UK Government and other devolved nations.
Sturgeon has said that "everything must be on the table to protect Scotland's place in Europe" after the UK voted to leave the EU, while the majority of Scots voted to stay.
Speaking ahead of the Brussels visit, she said: "My objective at this very early stage is firstly to raise awareness of the fact that Scotland voted differently in this referendum to the UK as a whole and that there is an aspiration and desire in Scotland, cross-party, to protect Scotland's relationship with the European Union and our place in the European Union.
"And secondly, to begin the process of mapping out and exploring what the options for Scotland might be.
"I'm very aware that this is a long process ahead of us, it's likely to be a difficult and challenging process, but I'm determined that we take every possible step to protect Scotland's interests at every stage of it."
The First Minister's diplomatic mission comes as the European Council summit, chaired by Tusk, continues.
The heads of state or government are meeting informally to discuss the political and practical implications of the referendum results after David Cameron outlined the UK's position on Tuesday.