Poland says the aircraft stayed in its skies for 42 seconds, forcing the Nato member to scramble its fighter jets. A Russian Mi-8 helicopter crossed nearly 1,000ft into Polish airspace on Wednesday morning as Russia pounded Ukraine with daytime strikes that killed at least seven people Key points and original sources are listed below.

• Poland says the aircraft stayed in its skies for 42 seconds, forcing the Nato member to scramble its fighter jets.S1

• A Russian Mi-8 helicopter crossed nearly 1,000ft into Polish airspace on Wednesday morning as Russia pounded Ukraine with daytime strikes that killed at least seven peopleS2

• The Mi-8 helicopter spent 42 seconds in Polish airspace, the Polish military said.S3