NATO will invite Russia to take part in a US-European missile defense shield at a summit today, a move that would herald the closest cooperation between the powers since the end of the Cold War. NATO leaders agreed on Friday to develop a missile system to protect the territory of all NATO member states in Europe and North America. It will be capable of intercepting long-range missiles fired from the Middle East. Russia will be invited to be involved in the system when President Dmitry Medvedev meets U.S. President Barack Obama and other NATO leaders at the summit in Portugal, but it remains unclear what role Moscow might play. The system would be designed to defend against intercontinental ballistic missiles fired from Iran or North Korea, but Russia is reluctant to join a programme that defines Iran as a potential missile threat.