LIMA — The top captives in Peru’s hostage crisis, which entered its 17th day on Jan. 3, took the brunt of tough posturing on both sides by losing their jobs, as rebels continued to say they could withstand siege conditions.Both President Alberto Fujimori and rebels of the Tupac Amaru Revolutionary Movement (MRTA) do not appear to be preparing for a prompt end to the standoff. Especially considering the uncompromising stands taken on Jan. 2. On Jan. 2, Fujimori replaced the country’s top antiterrorist official and security chief. He also named a new Supreme Court president to replace Moises Pantoja, whose term ended Dec. 31. The three are among the 74 hostages still being held by the Marxist rebels.Some commentators have said the move might have been made to reduce the value of the hostages to the rebels and signal the country’s attitude that its internal affairs would go on, despite the crisis. But it is not clear whether the changes were routine or indicative of the state’s annoyance with the officials’ security lapses that allowed the rebels to take the residence.