WASHINGTON (Reuters) - The United States on Thursday strongly condemned the assassination of Tunisian opposition politician Mohamed Brahmi and called for a thorough investigation to bring those responsible before the courts.

"This is not the first political assassination since Tunisia's revolution and there is no justification for such outrageous and cowardly acts in a democratic Tunisia," State Department spokeswoman Marie Harf told a daily briefing.

"We urge the Tunisian government to immediately conduct a transparent and professional investigation to ensure that the perpetrators are brought to justice in a timely manner," she added.

(Reporting by Lesley Wroughton; editing by Jackie Frank)