NATO Secretary General Jens Stoltenberg has ruled out deploying ground-based nuclear missiles to Europe.

At a press conference on Thursday in Warsaw, Poland Stoltenberg said the 29-nation alliance had already started planning for a world without the Intermediate-Range Nuclear Forces Treaty (INF).

The United States decision to suspend participation in the INF has prompted concerns of its European allies.

It formally suspended its obligations under the 1987 INF Treaty on February 2 and triggered the six-month withdrawal process, citing alleged Moscow’s violation of the deal.

UN Secretary-General Antonio Guterres had warned that Europe would be most vulnerable to any negative consequences of the potential collapse of the deal.

The agreement bans all ground-launched missiles, conventional or nuclear, with ranges of 310 to 3,400 miles.