ISTANBUL, May 14 (Reuters) - Turkey has not shut the door to Sweden and Finland joining NATO but wants negotiations with the Nordic countries and a clampdown on what it sees as terrorist activities especially in Stockholm, President Tayyip Erdogan's spokesman said on Saturday.

Erdogan surprised NATO members and the two Nordic countries seeking membership by saying on Friday it was not possible for Turkey to support enlarging the alliance because Finland and Sweden were "home to many terrorist organisations".

Sweden and its closest military partner, Finland, have until now remained outside NATO, which was founded in 1949 to counter the Soviet Union in the Cold War.

It wants NATO "to address the concerns of all members, not just some," Kalin said

Asked whether Turkey risked being too transactional at a time of war, and when Finnish and Swedish public opinion favours NATO membership, he said: "One hundred percent of our population is very upset with the PKK and FETO (Gulenist) presence in Europe."

"If they (Finland and Sweden) have a public concerned about their own national security, we have a public that is equally concerned about our own security," he said