AMSTERDAM (Reuters) - Human rights lawyers launched a legal challenge on Thursday to U.S. President Donald Trump’s executive order imposing economic sanctions on employees of the world’s permanent war crimes tribunal, arguing it breaches the U.S. constitution. A filing lodged at a district court in New York by the Open Society Justice Initiative, a public interest law centre that specialises in war crimes cases, names Trump, U.S. Secretary of State Mike Pompeo and seven other members of his administration. It argues that the executive order violates constitutional rights, including freedom of speech, and prevents the plaintiffs from carrying out work in support of international justice. “By issuing this outrageous order, the Trump administration has betrayed Washington’s long-standing support for international justice, snubbed its allies, and violated the U.S. constitution,” Open Society Justice Initiative executive director James Goldston said in a statement. “We are going to court to end this reckless assault on a judicial institution and the victims it serves.” Trump authorised U.S. economic and travel sanctions against employees of the Hague-based International Criminal Court and anyone supporting its work on June 12, citing their involvement in an investigation into whether American forces committed war crimes in Afghanistan. On Sept. 2, Pompeo said ICC prosecutor Fatou Bensouda had been blacklisted. The ICC has said the measures are an attack on the court, the system of international criminal justice and the rule of law more generally. European Union countries and rights groups have rejected the U.S. sanctions as detrimental to efforts to secure international justice for war crimes. Measures include freezing the U.S. assets of those who help the ICC investigate or prosecute American citizens without U.S. consent, and barring them and their families from the United States. The main target of the move is Bensouda, who was granted approval in March to investigate possible crimes committed in Afghanistan between 2003 and 2014. These include alleged mass killings of civilians by the Taliban as well as the alleged torture of prisoners by Afghan authorities and, to a lesser extent, by U.S. forces and the CIA. Announcing the executive order in June, U.S. Secretary of State Mike Pompeo described the ICC, established in 2002 by the international community to prosecute war crimes, genocide and crimes against humanity, as a “kangaroo court”. Trump administration officials also said it threatened to infringe on U.S. national sovereignty and accused Russia of manipulating it to serve Moscow’s ends.