"We cannot rule out that in case of a renewed escalation of armed hostilities [in Ukraine's east] we will, together with our allies, decide on expanding our support to Ukraine, including its defense," Schetyna said in his annual address to the Polish parliament.
Schetyna also called for an increased number of international monitors to be deployed to Ukraine.
Last month, the number of approved monitors from the Organization of Security and Co-operation in Europe (OSCE) in Ukraine was increased from 500 to 1,000.
The OSCE Special Monitoring Mission was first deployed to all regions of Ukraine in March 2014 before its mandate was extended until March 2016.
According to UN estimates, more than 6,000 people have been killed in Ukraine's east since an armed conflict between Kiev and the self-proclaimed republics of Luhansk in Donetsk erupted in April 2014.
