U.S. authorities now have statistical data from the ten Swiss banks being investigated by the United States for helping U.S. clients to dodge taxes, Swiss newspaper Neue Zuercher Zeitung reported on Saturday.

TagesAnzeiger, another Swiss newspaper, reported that the Swiss banks now had until Sept 23 to hand over more specific client data.

Credit Suisse , which is one of the banks under investigation, had already handed over data earlier in the week, while the nine other banks had handed over the data through an intermediary on Friday, NZZ said without citing any sources.

The newspaper also said the Swiss government had given them plenty of rope to do this.

Mario Tuor, spokesman for the Swiss department for international financial affairs, declined to comment on the NZZ and TagesAnzeiger reports, but he said: We are still going for a solution on the basis of existing legal rules in Switzerland.

Late on Friday, Reuters reported that the United States was drafting legal documents, seeking to force nearly a dozen Swiss banks and international banks with Swiss branches to disclose the identities of American clients that evaded taxes.

Also on Friday, Swiss newspaper Blick said that Switzerland had given the United States an estimate of the number of its citizens who used secret accounts to avoid paying taxes between 2002 and 2010.

Swiss foreign minister Micheline Calmy Rey said on Wednesday that Switzerland had given the U.S. statistical data about the extent of U.S. taxpayers, but had not handed over any bank client data.

Handing over statistical data is possible within the current Swiss law that protects banking secrecy.

Switzerland, a noted tax haven that is the global capital of offshore private banking, has been under attack from U.S. Justice Department and Internal Revenue Service officials conducting a broad criminal investigation into private banking services that U.S. authorities say enabled wealthy Americans to evade billions of dollars in taxes.

The Justice Department served a target letter in July on Credit Suisse, Switzerland's second-largest bank, notifying it that it was the focus of a criminal investigation. American authorities also are probing HSBC and smaller Swiss private banks and cantonal banks, including Basler Kantonalbank, Wegelin and Julius Baer .

The Justice Department is trying to determine the total volume of unreported accounts held at Swiss banks. Officials suspect the accounts hold assets in the tens of billions of dollars and possibly more.

(Reporting by Katie Reid; Editing by Toby Chopra)

Privacy