By Michael Voss BBC correspondent in Jerusalem

Thursday's suicide bombing in Jerusalem, which left 11 dead and dozens injured, was the first such attack since a snap general election was announced at the beginning of November.

If such attacks continue, they could prove a disaster for the opposition Labour party as it struggles to regain power on a platform of resuming negotiation with the Palestinians.

[Labour's message] is hard to sell at present

Labour has seen suicide bombings destroy its electoral hopes in the past and must fear that it could happen again.

But how much should we read into what is the 85th suicide bombing since the latest Palestinian uprising began two years ago?

Is this the start of a concerted attempt by Palestinian extremists to derail any chances of a comprehensive Middle East peace or is it just the latest bloody expression of continuing Palestinian anger and frustration?

New leader, old vulnerability

Labour have just elected a new leader to take them into January's general election.

Amram Mitzna, the mayor of Haifa and a former general, advocates returning to the negotiating table with the Palestinians without pre-conditions and an immediate withdrawal of Israeli settlers and troops from the Gaza Strip.

Mitzna's peace message could be drowned out

It is a hard message to sell at present. All the opinion polls show that the majority of Israeli voters prefer the hardline approach of the ruling Likud party. And with every new suicide bombing public opinion hardens still further.

"If the general election were held tomorrow Amram Mitzna would be in very bad shape," says Akiva Eldar, a political analyst with the Haaretz newspaper.

"The bombing is another message from the Palestinians that they are in charge, that they can dictate the results in elections."

Labour supporters remember only too well what happened in the 1996 elections following the assassination of Prime Minister Rabin. Initial opinion polls showed his successor Shimon Peres holding a 25-30% lead over his Likud rival Binyamin Netanyahu.

Mr Peres's lead was destroyed in a four-week blitz of suicide bombings in February and March 1996 which killed 62 Israelis.

It cost Labour the election as well as turning public opinion against the Oslo peace accords.

Talks flounder

It may be a coincidence but shortly after this latest general election was announced a meeting of Palestinian groups took place in Cairo hosted by the Egyptian Government.

The Palestinian Authority's Fatah movement held talks with the al-Aqsa Martyr's Brigades and Hamas in a bid to engineer a three-month ceasefire in order to get negotiations restarted.

Hamas has no interest in peace deals

In the end it did not work. Hamas and Islamic Jihad do not want any part of a peace deal with Israel and could be sidelined if Arafat achieved one.

As Palestinian analyst Zaid Abu Amr told Reuters: "It is wrong to assume the Hamas and Islamic movements would prefer the Labour Party to Likud. Hamas was largely responsible for the destruction of the peace process and seeks to replace the Palestinian Authority."

But Mahdi Abdl Hadi, head of the Palestinian think-tank Passia, told the BBC he believes that Thursday's killings carried a mixed signal:

"On one side it was a direct message to [Prime Minister Ariel] Sharon that any truce must be a two-way street with guarantees from the Israelis. Yes, it will have a negative impact on the election but Labour should not take it as a slap in the face."

In this murky world of Middle Eastern politics, it is also possible that other forces could be at play.

Friday's edition of the Jerusalem Post quotes an unnamed senior official in the prime minister's office as saying that "the current wave of terrorism is part of an attempt by Iran, Syria and Hezbollah to escalate the situation within the territories to disrupt the US's campaign against Iraq".