NATO Secretary General Anders Fogh Rasmussen has called for a new strategic partnership with Russia.
In his first major foreign policy address since taking office in August, Mr Rasmussen called for a joint review with Moscow of global security challenges.
The former Danish prime minister was speaking in Brussels on Friday after the United States announced it is shelving plans for defence missile bases in Poland and the Czech Republic. A new plan will combine land and sea-based interceptor rockets.
Mr Rasmussen urged the US, NATO and Russia to study a joint missile defence system.
He also called for Moscow's co-operation on Afghanistan and Iran.
Russia said on Friday it has cancelled plans to station missiles in Kaliningrad - between Poland and Lithuania.