One woman was killed and more than 25 people were injured when a bomb exploded at a bus stop in west Jerusalem on Wednesday afternoon, shaking Israelis already unsettled by stepped-up Palestinian rocket attacks from Gaza.

Israeli officials warned they will counter the growing violence — and are even considering another military intervention in Gaza.

Israeli Prime Minister Benjamin Netanyahu and Defense Minister Ehud Barak said they “”would not tolerate”” an attack against civilians, and police spokesman Micky Rosenfeld said that the first bombing to strike Israel in several years doesn’t mean the country has “”gone backwards”” to a time when Israelis were accustomed to such attacks.

“”We do not believe that this is a return to that time. Jerusalem police are acting to find the terrorists who are responsible for this attack, and to secure the city,”” Rosenfeld said.

The al-Quds Brigade, the armed wing of the Palestinian Islamic Jihad, claimed responsibility and vowed to continue targeting cities deep inside the country.

“”From now on, there are no more red lines for the resistance as long as the enemy … keeps killing civilians,”” spokesman Abu Ahmad said. In the West Bank, Palestinian Prime Minister Salam Fayaad condemned the attack, and expressed condolences for the victims.

The scene outside Jerusalem’s bus station and convention center was chaotic Wednesday afternoon, as thousands gathered at the scene of the bombing. Shattered glass from the windows of the bus littered the pavement, and the sidewalk outside the bus was smeared with blood.

Eli Yishai, Israel’s interior minister, rushed to the scene and called for swift Israeli retaliation. “”With these murderers, these terror organizations … we must act, or we will lose our deterrence.””

In a briefing to McClatchy Newspapers, a high-ranking intelligence official said Israel would consider launching a military operation against the Gaza Strip for the first time since Operation Cast Lead, a 22-day offensive in Gaza that left 1,400 Palestinians and 13 Israelis dead in December 2008.

“”Israel cannot afford to lose its deterrent power,”” said the official, who couldn’t be named as a matter of policy. “”It has been quiet because they have been afraid that it is not worth their while to attack. They must continue to think that.””

Netanyahu’s office confirmed that he had held talks with top military and defense officials to evaluate an “”appropriate”” response to the violence along the Gaza border.

In Gaza, militants and the Israeli Defense Forces have exchanged in tit-for-tat violence, with militant groups firing more than 60 rockets into Israel over the past week. Several Israelis have been injured in those attacks. Israel has responded with targeted air strikes. In an incident Tuesday, an IDF tank shell misfired and killed four Palestinian civilians in a home near a site where militants were attempting to fire rockets into Israel, the IDF said.

“”No country would be prepared to absorb protracted missile fire on its cities and civilians, and of course the State of Israel is not prepared to,”” Netanyahu said. “”It could be that this matter will entail exchanges of blows, and it may take a certain period of time, but we are very determined to strike at the terrorist elements and deny them the means of attacking our citizens.””

Israeli paramedic Zaki Heller was one of the first to arrive on the scene of Wednesday’s attack. He said that a small bag, usually used to shop in the nearby market, contained a four-pound bomb packed with small ball bearings. The bag appears to have been placed near a telephone pole outside the bus stop, where people waiting for several bus lines were standing.

When Heller arrived at the scene, he saw two women with severe injuries lying on the pavement next to the bus.

“”Other people were all around nursing their injuries. It appears those injured were queuing for the bus when the explosion happened. If the bomb has been inside the bus, it would have been much, much worse,”” he said.

Tzarfat Avivya, 58, was approaching the bus stop when the bomb went off. It’s the same bus that she and her neighbors ride each day to the suburbs west of Jerusalem.

“”It’s my bus, I take it every day. I can’t believe it. Who would do such a thing? I can’t believe it, it could have been me,”” she said. She described a scene of children crying in the street searching for their parents in the aftermath of the bombing. “”It just feels like we have gone backwards four years ago to the intifada.””