Sweden's ruling Social Democrats have begun an internal debate about joining NATO following Russia's invasion of Ukraine.
Members of the party -- who have previously opposed Swedish membership of the alliance -- have met to discuss the country's strategic situation.
Deputy party leader Tobias Baudin said Monday's debate will be a "broader discussion than just a yes or no question on NATO membership".
"We have to seek a broader understanding of what is happening in the world around us and understand the advantages and disadvantages of the current security policy line," Baudin said.
The "security policy dialogue" should be completed before the summer, he added in a statement.
Swedish Prime Minister Magdalena Andersson said in a u-turn last month that she "does not rule out" a bid to join NATO.
Neighbouring EU member state Finland is also set to decide on joining the military alliance by the summer.
Support for membership almost doubled since Russia invaded Ukraine on February 24, jumping to almost 50% in Sweden and 60% in Finland.
The issue is also set to be a major campaign issue in the upcoming Swedish general election on 11 September.
Ulf Kristersson, leader of Sweden's opposition Conservative party, has said he would apply to join NATO if he wins a majority in parliament.
Russia meanwhile has warned Finland and Sweden against joining NATO, arguing the move would not bring stability to Europe.
"The alliance remains a tool geared towards confrontation," Kremlin spokesman Dmitry Peskov told reporters.