Sikorski said there is no predetermined definition of when Russian actions would cross a line requiring a firm response.
He recalled that Poland and Estonia had requested consultations under Article 4 of the North Atlantic Treaty following violations of their airspace by Russian drones and aircraft.
According to the Financial Times, European intelligence agencies have warned of an increase in Russian sabotage operations.
Representatives of five intelligence agencies told the newspaper that Russian agents were targeting the leadership of European arms companies.
German intelligence services warned that Russian activities were entering a potentially deadly phase.
Sikorski called on European allies to close Russian consulates, reduce the number of Russian diplomats and restrict their freedom of movement.
He also proposed requiring Russians entering the EU to hold biometric passports, making it harder for agents to travel under false identities.
Sikorski supported limiting tourist visas issued to Russian citizens. EU member states issued nearly 500,000 tourist visas to Russians last year, according to the report.
He also called on EU countries to identify Russia as responsible for attacks when sufficient evidence is available.
EU foreign ministers were due to discuss possible restrictions on Russian diplomats and tourists in Luxembourg on Monday.
During a recent visit to London, Sikorski said he would seek an invitation for Poland to next year's G20 summit in Manchester.
In return, Warsaw would support closer relations between the United Kingdom and the EU.
"We think the EU was better and would be better with Britain in it," he said.
He added that Poland expected reciprocity, arguing that its economic development over the past 30 years demands recognition.
(sp/gs)
Source: PAP/IAR