Google and Yahoo have res-ponded to inquiries by the Department of Justice's antitrust division about an alliance they launched this month that had been expected to improve Yahoo's bargaining position with Microsoft. Yahoo, the search company that is seeking to fend off an unsolicited $43bn takeover bid by the Redmond software group, yesterday said it had "proactively" kept the DoJ informed about its intention to conduct a limited test with its rival, Google, and that it had provided the DoJ with information about the test.

A spokesman for Google said: "We informed the justice department before we launched this test and we have been responsive to their questions about it."