A suicide bomber has killed at least seven people and injured about 20 in an attack on a bus in Jerusalem.
The bomber was said to have been disguised as a religious Jew
The attack - at the beginning of the Israeli working week - came just hours after the highest level talks between Israeli and Palestinian leaders in more than two years.
A second suicide bomber blew himself up as emergency crews arrived at the scene of the blast in the north of the city - but failed to cause any more casualties.
Israeli Prime Minister Ariel Sharon has delayed leaving the country for a scheduled meeting with President George W Bush in Washington.
The Israeli army imposed a temporary curfew on the West Bank town of Ramallah, in the belief that at least one of the bombers came from there.
And the Israeli security cabinet was meeting on Sunday to discuss further responses to the attacks.
Mr Sharon held his first official meeting with his Palestinian counterpart Mahmoud Abbas, better known as Abu Mazen, on Saturday night.
The talks, which focused on security, were inconclusive but correspondents say the mere fact that the two men met was a step forward.
Two Israelis - a husband and his pregnant wife - were killed in another suicide attack in the West Bank town of Hebron shortly before the talks began.
Witnesses said a huge blast ripped the Jerusalem bus apart shortly before 0600 (0300 GMT) at a busy junction known as French Hill.
Police said a suicide bomber had boarded the vehicle and detonated explosives strapped to his body.
When emergency services arrived to clear the area, they approached a man behaving suspiciously who then blew himself up.
The French Hill junction has been targeted by bombers before.
At least 20 people were injured in the suicide attack
It is a busy intersection where many people board buses, including Jewish settlers moving in and out of the West Bank.
Although early, the location would have been quite busy as Sunday is the first day of the working week in Israel.
Jerusalem police commander Mickey Levy told Israel Radio that the bus had left the suburb of Pisgat Zeev.
"The explosive was large and the bus was shattered," he said.
At least eight people, including the suicide bomber, were killed in the first blast and at least 20 injured, officials say.
It is reported that the bomber who boarded the bus was disguised as a religious Jew - the same tactic was used in the Hebron attack on Saturday.
Also in the West Bank on Saturday night, two gunmen were shot dead by Israeli forces when they infiltrated the Jewish settlement of Shaarei Tikva injuring two residents.
Earlier in Gaza, Israeli soldiers shot and killed an armed Palestinian and wounded nine others during clashes in Beit Hanoun.
ROADMAP MAIN POINTS
Phase 1 (to May 2003): End of terrorism, normalisation of Palestinian life and Palestinian political reform; Israeli withdrawal and end of settlement activity; Palestinian elections
Phase 2: (June-Dec 2003) Creation of an independent Palestinian state; international conference and international monitoring of compliance with roadmap
Phase 3 (2004-2005): Second international conference; permanent status agreement and end of conflict; agreement on final borders, Jerusalem, refugees and settlements; Arab states to agree to peace deals with Israel
The violence overshadowed the talks between Mr Sharon and Abu Mazen, which the BBC's James Reynolds in Jerusalem says focused on the crucial area of security.
Israel is demanding an end to attacks before it will move ahead with the implementation of the roadmap for peace which envisages a Palestinian state.
At the talks with Abu Mazen, Mr Sharon urged the Palestinian Authority to tackle armed groups, particularly in Gaza.
But Abu Mazen insisted he could only take security steps once Israel decided to accept the roadmap.
Correspondents say the fact that there has been no immediate breakthrough is no surprise considering the gulf still separating the two sides.
However, mediators say it is encouraging that the meeting - the first such summit since the Palestinian intifada erupted in September 2000 - even took place.
Mr Sharon is expected to seek a number of modifications to the roadmap when he meets Mr Bush.