The United States, Britain and Canada are to conduct a counter-terrorism exercise next month focusing on inter-government communication in the event of an attack, the UK government said on Friday.

The tripartite exercise, from April 4 to 8, aims to test “simultaneous responses to internationally-linked terrorist incidents,” British officials said.

There will be no public activity by police or armed forces, the focus will be on strategic communication between the powers. The precise scenario will not be released before it takes place.

Britain is calling its part of the exercise “Atlantic Blue,” Washington has opted for “TopOff3,” Canada for “Triple Play.”

“It is vital we make every effort to enhance and develop our resilience to this threat by working closely with our international colleagues,” British Interior Minister Hazel Blears said in a statement.

“Exercise Atlantic Blue provides an excellent opportunity to do this, through sharing best practice on emergency planning and response procedures.”

Officials said the role-play was designed to enhance international emergency preparedness and did not reflect specific known threats to any of the three nations.

The British government also released a statement from Secretary of Homeland Security Michael Chertoff.

“By responding realistically to simulated attacks, we are able to identify our strengths and weaknesses and make our national response system stronger,” it quoted him as saying.