After a stray missile crashed in Poland last week, Germany offered Warsaw the Patriot missile defense system to assist defend its airspace, Defence Minister Christine Lambrecht told a newspaper on Sunday.

After the event, which at first aroused concerns that the conflict in Ukraine could cross the border, the German government had previously said that it would provide its neighbor with more assistance in air policing using German Eurofighters.

The missile that hit Poland last week, killing two people, appeared to have been fired by Ukraine’s air defences rather than a Russian strike, NATO chief Jens Stoltenberg has said.

Ground-based air defense systems such as Raytheon’s Patriot are built to intercept incoming missiles.

After Russia invaded Ukraine in February, NATO proceeded to bolster air defenses in eastern Europe. In October, a group of more than a dozen NATO allies, led by Germany, launched a project to collectively acquire Patriot-compatible air defense systems.

When Germany was a NATO frontline state during the Cold War, it had 36 Patriot units. There are 12 Patriot units in the German military at the moment, two of which are stationed in Slovakia.