Moscow’s attacks have targeted Ukraine’s power grid ahead of winter in what officials say is meant to demoralize civilians. Polish Prime Minister Donald Tusk said two incidents along Ukraine’s borders with Poland and Moldova this week were a preview of potential intensified Russian provocations. Key points and original sources are listed below.

• Moscow’s attacks have targeted Ukraine’s power grid ahead of winter in what officials say is meant to demoralize civilians.S1

• Polish Prime Minister Donald Tusk said two incidents along Ukraine’s borders with Poland and Moldova this week were a preview of potential intensified Russian provocations.S2