JERUSALEM (AFP) - Israel's foreign minister and Kadima party number two challenged Ehud Olmert's party leadership on Thursday, calling for an unprecedented primary amid demands he quit as premier over graft suspicions. "Kadima should start preparing now for any possible scenario, including elections. I am a big believer in primaries," said Tzipi Livni. "I believe most of the public should be involved in the election of the leadership. This way we will be able to retrieve the public's support in Kadima," she told reporters in Jerusalem. At no point, however, did Livni explicitly call for Olmert to step down as party leader or as premier. Jewish-American financier Morris Talansky recently testified before a Jerusalem court that he had given Olmert vast amounts of cash stuffed into envelopes. Kadima, founded hastily by former prime minister Ariel Sharon before the March 2006 elections, does not have an internal mechanism for ousting a leader or holding party leadership elections. Israel has been abuzz all day with speculation that a snap election would be held in late 2008 or early 2009. That was set off after a key ally in the government coalition, Defence Minister and Labour party leader Ehud Barak, joined calls for Olmert to step down over allegations he illegally received vast sums of cash from a US financier. As pressure on Olmert mounted, Attorney-General Menahem Mazuz decided after a meeting with the state prosecution on Thursday to speed up the investigation, the justice ministry said. "We can't ignore recent days' events. The issue is not only legal, it is not only a criminal question," Livni said. "These are not the prime minister's personal issues. These are questions of values and norms we want to apply." Olmert, whose term ends in late 2010, has said he had no intention of quitting, although an opinion poll on Thursday found that 70 per cent of people surveyed thought he should go. "I am going to continue to exercise my functions," the embattled prime minister said on Wednesday. Opposition lawmakers have also claimed that the scandal-tainted premier lacks the moral authority to lead peace efforts that could shape the future of the Middle East.