JERUSALEM — Israeli police unveiled stunning new allegations against Prime Minister Olmert today accusing him of getting multiple sources to pay for the same trips abroad so he could pocket the difference.

The new details — made public shortly after police questioned Mr. Olmert for a third time in a burgeoning corruption scandal — could make it even tougher for the embattled Israeli leader to hang on to his job and pursue peacemaking with the Palestinian Arabs.

After the questioning, police announced they had widened their investigation to include the funding of trips abroad made by Mr. Olmert when he was Jerusalem mayor and then a Cabinet minister before he was elected prime minister in 2006.

The revelations indicated the corruption scandal was larger than originally thought and the suspicions were the gravest brought in the case since Mr. Olmert was accused of accepting illicit funds in May. The new accusations were expected to make Mr. Olmert’s fight for political survival much more difficult.

According to the new allegations, police believe Mr. Olmert illicitly took some $100,000 by deceiving multiple sources into thinking they were paying for the same trip.

Since the corruption case against Mr. Olmert first broke in May, Mr. Olmert has denied any wrongdoing, saying he never took money for his private use. He has promised to resign if indicted.

Investigators came to Mr. Olmert’s official Jerusalem residence today to grill him for more than two hours in connection with the probe, which centers on hundreds of thousands of dollars he allegedly received from an American Jewish businessman before becoming Israel’s leader in 2006.

Mr. Olmert served as Jerusalem mayor for 10 years until 2003, when he was appointed trade minister in Prime Minister Sharon’s government. He held that position until 2006.

“While serving as mayor of Jerusalem and as minister of industry and trade, (Olmert) is suspected of seeking funding for flights abroad in his official capacity from several sources at the same time … including the state,” the Justice Ministry and police said in a joint statement.

Each of these sources was asked to pay in full for the same flight, it added.

Police suspect that the “considerable sums” that remained after the flight was paid for “were transferred by Mr. Olmert to a special account his travel agency administered for him. These monies were used to finance private trips abroad by Mr. Olmert and his family,” the statement said.

Police officials said Mr. Olmert also billed multiple sources for other expenses, such as hotels, on dozens of trips abroad — with the illicit funds amounting to some $100,000. All information from the police outside the official statement was obtained on condition of anonymity because the case is still under investigation and officers were not authorized to expand on the statement publicly.

A senior police officer with the National Fraud Unit said the Rishon Tours travel agency “acted like a bank branch for the Olmert family.” Before going abroad, they’d contact the agency to check the balance in Olmert’s account there and “order tickets,” he said.

The agency, he said, also took care of hotel and other expenses the family incurred. No one answered the phone at the agency’s offices today, a short business day at Israel because of the Jewish Sabbath beginning at sundown.

According to the new allegations, Mr. Olmert asked the state to pick up the tab for his trips and also approached leading Israeli companies for funding, the police official said. Companies paid for his trips even when he was trade minister and responsible for overseeing corporate practices — raising suspicions of conflict of interest and breach of trust, he said.

Through a spokesman, the prime minister insisted he had broken no laws.

“Prime Minister Olmert is convinced that he is innocent of any wrongdoing and firmly believes that as this investigation continues, that innocence will become apparent to all,” the prime minister’s spokesman, Mark Regev, said.

Mr. Regev would not comment on the substance of the new suspicions.

The whiff of corruption has clung to Mr. Olmert throughout his more than three decades in politics, though he has never been convicted of any wrongdoing. But this latest case — the fifth opened against him since he became prime minister — could end his political career.

In May, a businessman, Morris Talansky, testified that he gave Mr. Olmert hundreds of thousands of dollars in cash-stuffed envelopes, and that some of those funds went to fund expensive cigars, hotels and other luxuries.

The testimony sparked a public outcry, further tarnishing the prime minister. Mr. Olmert’s Kadima party plans a primary election in September that could replace him as leader.

The turmoil in Israeli politics is likely to hurt an American-backed initiative to forge the outline of a peace deal between Israel and the Palestinian Arabs by year’s end. It also threatens to derail recently renewed peace talks between Israel and Syria.