MOSCOW — Russia’s security service head said Saturday that two suspects in the killing of leading opposition figure Boris Nemtsov have been detained. Russian news reports later cited an official as saying one of them had served with police troops in Chechnya.

The short and vague announcement of the detentions by Federal Security Service director Alexander Bortnikov prompted only skepticism and weak satisfaction from his comrades.

Bortnikov, in comments shown on state television, said the two suspects were from Russia’s North Caucasus region, but gave no details other than their names.

He said they were “suspected of carrying out this crime,” but it wasn’t clear if either of the suspects was believed to have fired the shots that killed Nemtsov as he and a companion walked over a bridge near the Kremlin on Feb. 27. No charges were immediately announced, but the two were expected appear in a Moscow court Sunday.

Bortnikov didn’t say where the detentions took place, how they were conducted or what led agents to the suspects. However, the state news agencies Tass and RIA Novosti said they were detained in Ingushetia, a republic bordering Chechnya, citing Ingush Security Council chief Albert Barakhoev.

One of them, Zaur Dadaev, served in a battalion of Interior Ministry troops in Chechnya, Barakhoev was quoted as saying.

He said the other, Anzor Gubashev, had worked in a private security company in Moscow, according to the reports.