He made the remarks on Tuesday during his visit to Vilnius where he met with Lithuanian Foreign Minister Gabrielius Landsbergis.
"I do not wish to bind myself to any kind of timeframe in this period, this time during the process," the minister told reporters, asked whether Sweden could become a NATO member by the upcoming NATO summit in Vilnius in the summer.
In his words, Stockholm, Helsinki and Ankara have a trilateral agreement defining a clear path towards membership.
"All conditions have to be fulfilled by all three parties. That also means that there are items in this document which is of great interest for Sweden, namely, cooperation on crime fighting. Today, we see people commit crimes in Sweden and then head off to Turkey," Billstrom said, adding that Sweden is in constant contact with Turkey.