Despite Denial, Peru's Police Seem to Plan Hostage Rescue
There are reports that Peruvian police forces are burrowing tunnel to Japanese Ambassador's residence, as part of plan to rescue hostages; Defense Min denies existence of any tunnels, and a police official dismisses rebels' reports of hearing digging noises as 'an invention'; Pres Alberto K Fujimori says he remains dedicated to resolving crisis peacefully, but he adds that peaceful approach will last only as long as rebels 'fully respected the life and health of the hostages'; photo (M)