BERLIN (AP) — Germany's highest court on Tuesday rejected a case brought by Yemeni plaintiffs who argued the German government failed in a duty to protect relatives who they say were killed in a 2012 drone strike against an attack controlled with help from a U.S. military base in Germany.

Ruling in a case that has been making its way through the German judicial system for over a decade, the Federal Constitutional Court found the German government can have a concrete duty to protect foreign citizens abroad in some cases.

But it said that only could apply when there is a “sufficient connection” to the German state's authority and “a serious danger of systematic violation” of international law. It found the case at hand didn't fulfill the requirements.

The plaintiffs argued the U.S. military's Ramstein Air Base in southwestern Germany plays a key role in relaying flight control data used for armed drone strikes in Yemen via a satellite relay station set up with the knowledge and approval of the German government.

A lower court ruled in 2019 that the German government had partial responsibility to ensure U.S. drone strikes controlled with help from Ramstein are in line with international law, but judges stopped short of ordering the ban human rights activists had called for. The following year, a federal court overturned the ruling.

The supreme court said the evidence submitted didn't lead to the conclusion the U.S. applied criteria that were unacceptable under international law in determining legitimate military targets in Yemen.

The European Center for Constitutional and Human Rights, which argued the case for the Yemeni plaintiffs, said “at a time when the adherence of state action to international law is increasingly being called into question, the court has failed to send a strong signal,” adding that “individual legal protection remains a theoretical possibility without practical consequences.”