(Adds details, quotes, Constituent Assembly suspension)
TUNIS, Aug 6 (Reuters) - Tunisian police shot dead an Islamist militant on Tuesday in a suburb on the outskirts of the capital Tunis, an interior ministry official said.
The incident comes after a spike in Islamist militant attacks in the country, which is also grappling with the worst political crisis since the 2011 ouster of its autocratic president.
Also on Tuesday, the head of the Constituent Assembly, which is only weeks away from finishing a draft constitution and electoral law, suspended the body's work until the Islamist-led government and secular opposition opened up a dialogue.
The opposition, emboldened by events in Egypt where the army toppled the elected Islamist president, is trying to oust the government led by the moderate Islamist Ennahda party.
But the party's chief Rachid Ghannouchi said removing Prime Minister Ali Larayedh or dissolving the Assembly was a "red line", and challenged the opposition to a referendum to decide the matter.
Security forces are facing a surge in violence blamed on militants. In one of the biggest attacks on Tunisian security forces in decades, gunmen killed eight Tunisian soldiers last week near the Algerian border. (Reporting by Erika Solomon; Editing by Mike Collett-White)