BEIRUT (AP) — The shattered city of Beirut marked a week since the catastrophic explosion that killed at least 171 people, injured thousands and plunged Lebanon into a deeper political crisis. Thousands of people marched near the devastated port, remembering those who died in the most destructive single blast to hit the country. They observed a minute of silence at 6:08 p.m. local time, the moment on Aug. 4 that thousands of tons of ammonium nitrate exploded in the city’s port where it had been stored for more than six years, apparently with the knowledge of top political and security officials. At that moment, church bells tolled and mosque loudspeakers recited a call to prayer.