The U.S. government and Swiss bank UBS AG have initialled agreements to settle their tax evasion dispute, a U.S. government attorney said on Wednesday, ending weeks of tough negotiations between the two sides.

U.S. Department of Justice tax division attorney Stuart Gibson told a status conference call that U.S. charges against UBS would be dropped once a final deal was formally signed.

The parties have initialled agreements. It will take a little time for the agreements to be signed in final form, Gibson told U.S. District Judge Alan Gold.

When the final documents are signed the parties will file a stipulation of dismissal, he added.

The settlement was expected to involve the disclosure to U.S. authorities of the names of thousands of wealthy American clients of UBS suspected of using offshore accounts at the bank to conceal assets and evade U.S. taxes.

Washington's legal case against UBS, the world's number two wealth manager by managed assets, had strained relations between the two countries, because it challenged Switzerland's jealously-guarded bank secrecy laws.

The U.S. government and UBS said on July 31 they had reached an agreement in principle on major issues in the case, but negotiations have focused on the legal details of how to allow the transfer of substantial UBS client data to Washington while respecting Swiss bank secrecy laws.

The case has big implications not just for Switzerland, whose private banks manage around $2 trillion of foreign wealth, but for the entire offshore banking industry.

(Reporting by Pascal Fletcher, Jim Loney, Jane Sutton; Editing by Pascal Fletcher)