Update at 12:25 p.m. ET. Recapping the news:
"A bomb struck a crowded bus stop in central Jerusalem Wednesday, killing one woman and wounding more than 20 other people in what authorities said was the first major Palestinian militant attack in the city in several years," The Associated Press writes. "The bombing brought back memories of the second Palestinian uprising last decade, a period in which hundreds of Israelis were killed by suicide bombings in Jerusalem and other major cities."
From Jerusalem, NPR's Lourdes Garcia-Navarro says that the blast "echoed through the city" and that because it happened at the beginning of the afternoon rush hour, "the area was brimming with people traveling from work."
Update at 11:35 a.m. ET: State-run Israel Radio says one woman has died from injuries suffered in the blast, The Associated Press says. Haaretz also says there was one fatality and that "at least 30 people were wounded."
Update at 10:20 a.m. ET: NPR's Lourdes Garcia-Navarro says 25 people were hurt in the bombing that occurred just as rush hour started.
Update at 9:45 a.m. ET: Sheera Frankel went to the scene in central Jerusalem. She reports authorities believe a bomb was concealed in a bag. Hundreds of police and Israeli Defense Forces troops are swarming over the area looking for any hidden parcels.
Sheera says at first, people nearby believed the noise was thunder and lightning before realizing the explosion was an attack.
Update at 9:35 a.m. ET: Haaretz says 25 people were wounded by an explosive device that went off near two public buses. The report cites Jerusalem emergency officials in Jerusalem who say no one died but four people are badly hurt.
Update at 9:28 a.m. ET: Israel Army Radio and the Jerusalem Post report at least 20 people are hurt.
Our original post: Sirens are blaring in Jerusalem, NPR's Lourdes Garcia-Navarro reports, as authorities respond to the scene of what's said to have been an explosion on a bus or at a bus stop.
Reuters says there are "dozens of casualties" and that "scores of ambulances converged on the area, near the central bus station and a city conference hall in ... downtown Jerusalem."
Haaretz says "an explosion rocked a public bus on Wednesday afternoon outside the International Convention Center, just opposite the central station in Jerusalem. At least 18 people were wounded in the incident, according to local media. The casualties were being evacuated to the Hadassah Hospital in Ein Karem."