US envoy John Wolf is in Jerusalem in an attempt to salvage the American-backed roadmap for peace. BBC News Online looks at where the various parties in the conflict stand.
US President George W Bush
President Bush emerged from the recent Aqaba summit full of optimism for the future of the Middle East roadmap. He has become personally involved in the region after a period of disengagement and was enticed by the prospects of success.
"A lot of presidents have tried," he said as Air Force One left Aqaba. "Every president should try. We ought to use the prestige of America to try for peace... [And] maybe history is such that we can achieve it."
President Bush was upbeat about the roadmap after the Aqaba summit
Although he vowed to remain engaged in the peace plans, renewed violence has put his personal commitment to the test. Some commentators say he may back off rather than risk personal humiliation.
US officials are now guarded about the president's direct role in the coming days and weeks. They say there are no plans "at the moment" for him to intervene directly.
Since the renewal of violence, Mr Bush has relied on his top aides, mainly Secretary of State Colin Powell and security adviser Condoleezza Rice, to maintain pressure on Israeli leaders and keep the peace plan alive.
However, in public remarks made after the failed Israeli attempt to assassinate a Hamas leader, he did show that he was prepared to speak bluntly to Israeli Prime Minister Ariel Sharon. He said the attack would undermine the efforts of Mr Sharon's Palestinian counterpart Mahmoud Abbas to rein in the militants.
Commentators say direct presidential involvement is important to restore a sense of momentum to the roadmap.
Israeli Prime Minister Ariel Sharon
Over the past two weeks, Ariel Sharon has acted in many different, apparently conflicting ways. His qualified acceptance of the roadmap, his remarks about ending occupation and his decision to dismantle some Jewish settlement outposts in the West Bank have disappointed may Israelis on the right.
However, his tough rhetoric about fighting the Palestinian militants to the bitter end and the Israeli helicopter strikes in Gaza have disappointed Israelis on the left.
Ariel Sharon is still popular with most Israelis
Mr Sharon, however, remains a popular leader. Correspondents say that most Israelis see his focus on security as a good thing and if that means taking on Hamas and putting aside some of the demands of the roadmap, then so be it.
It is not clear whether or not Mr Sharon's stated strategy to destroy Hamas is more than psychological warfare. But, whether it goes ahead or not depends to a large degree on the United States.
Mr Sharon has, until recently, treated his Palestinian counterpart Mahmoud Abbas with courtesy. But, on Thursday, he hit out at his administration for failing to bring the militants to heel.
A day after the Jerusalem suicide attack, he described Mr Abbas as "a featherless little chick who needs to be assisted in his fight against terrorism until his feathers start growing".
Palestinian Prime Minister Mahmoud Abbas
Mahmoud Abbas, otherwise known as Abu Mazen, pledged to end the armed Palestinian uprising at the Aqaba summit.
But his calls for the abandonment of armed resistance in favour of negotiations to achieve a Palestinian state under the roadmap were rejected by the Palestinian militant groups. They say the Palestinian prime minister gave too much weight to Israeli concerns.
Correspondents say the Palestinian prime minister appears to be powerless to prevent the suicide attacks, given the weakness of his security forces and Palestinian anger at the Israeli missile strikes in the Gaza Strip.
Mahmoud Abbas' position appears to have been undermined
Palestinian political analyst Ali Jarbaqi said Mahmoud Abbas had been stymied before he could even begin implementing measures agreed at the 4 June summit.
"He has been blindsided by the interlocking violence of the Israeli right and Hamas, and by Sharon's refusal to lift the closure, stop the incursions and the assassinations. If the US does not intervene strongly and quickly, the roadmap is dead."
He added that Abu Mazen's [reformist] government had been unable to get off the ground because "it can't convince the public to place a stake in the roadmap".
Palestinian leader Yasser Arafat
Yasser Arafat has been sidelined by the US and the Israelis.
But it appears that he is keen to play a central role.
After the bus bombing in Jerusalem, he called publicly for an immediate ceasefire - beating by half an hour a similar statement made by Mahmoud Abbas.
Yasser Arafat appears to want to play a central role
Correspondents say that by issuing a public ceasefire call after the bomb, he was in effect saying that he was the only leader with the ability to bring about a ceasefire.
Shortly after the Aqaba summit, three Palestinian militant groups, Hamas, Islamic Jihad and the al-Aqsa Martyrs' Brigade, attacked an Israeli army base in Gaza. It was a direct challenge to Abu Mazen, who had been trying to persuade the militants to halt the attacks.
A few days later, Hamas, which later carried out a suicide bombing in Jerusalem, threatened to blow Israel up and tear it to pieces in response to Israeli air strikes.
The militants have vowed to tear Israel to pieces
Hamas has emerged as one of Israel's most implacable enemies over the past few years.
According to the Israeli army, over the past two-and-half years Hamas has killed more than 240 Israelis and wounded 1,400 others in 73 suicide bombings.
The group advocates armed struggle as the only means to defend the Palestinian cause and wants a future state to cover the whole of historic Palestine, from the Jordan river to the Mediterranean, rejecting the very existence of Israel.
Shortly after the outbreak of the uprising 32 months ago, Israel embarked on a policy of assassination against Hamas leaders in the West Bank and Gaza Strip.
The BBC's Arabic affairs analyst Magdi Abdelhadi says Hamas's popularity among the Palestinians is partly due to the fact that it organises clinics and schools in towns and refugee camps where many feel let down by the Palestinian Authority.