Alongside the increasing security concerns of former Warsaw Pact countries, there was significant debate in the early 1990s about the merits of enlargement. Rather than jump straight into enlarging Nato, the
Partnership For Peace (PfP) was established in 1994 and included NACC members as well as former Soviet Asian countries, such as Kyrgyzstan and Kazakhstan. The result was a greater formalisation of the security arrangements, initially developed by the NACC, into a structure that allowed for PfP members to engage in Nato peacekeeping operations in the former Yugoslavia.
Russia was a participant in these new security arrangements, and was keen to clarify that Nato enlargement was not a security threat to Russia. The then president of Russia, Boris Yeltsin, wrote in a September 1993
letter to the then US president, Bill Clinton: “Any possible integration of east European countries into Nato will not automatically lead to the alliance somehow turning against Russia.” So it was being clearly signalled that Russia did not object to the direction Europe’s new security architecture was following.