Canada is sending six CF-18 fighter jets to eastern Europe as part of a NATO operation in response to the ongoing crisis in Ukraine.

Prime Minister Stephen Harper announced the decision in Ottawa Thursday.

He said the jets are being sent “in response to a NATO request” as it expands its operations in eastern Europe.

“Obviously this in response to the situation that’s developing there,” Harper told reporters, particularly over concerns about the “expansionism and militarism” of Russian President Vladimir Putin in Ukraine.

As many as 20 Canadian Forces staff officers will be sent to NATO headquarters in Brussels as it ramps up its response to Russia’s incursion in eastern Ukraine.

Secretary General Anders Fogh Rasmussen announced Wednesday that NATO will deploy additional resources to former Eastern Bloc countries, including jets and warships.

Rasmussen announced that the United States, Britain, Denmark, Poland, Portugal and Germany had all agreed to send fighter jets for air patrols over the region.

"We do have the necessary capacity to implement these measures that have been recommended by our military authorities," Rasmussen said Wednesday in Brussels.

"We already know that some Allies will come forward with concrete contributions and I'm sure that more will follow."

NATO is responding to growing violence in eastern Ukraine, where pro-Russian activists are taking hold of government and media buildings, declaring independence and demanding referendums to join Russia.

This has led to violent clashes with Ukrainian troops and fears that Putin will move to annex more of eastern Ukraine after seizing the Crimean Peninsula.

“Canada remains steadfast in its support for Ukraine and will not stand idly by while its sovereignty and territorial integrity are threatened,” the prime minister said in a written statement.

“Together with our allies, we will continue to monitor events closely and take coordinated action to enhance Europe’s security and show our support for the people of Ukraine.”

Foreign Affairs Minister John Baird will visit the region in the coming days, a trip that includes stops in the Czech Republic, Slovakia, Poland, Latvia and Estonia.