SAN FRANCISCO -- Google said Friday it is postponing a planned online advertising tie-up with Yahoo to allow more time for US anti-trust regulators to consider the ramifications of the deal.

"When we announced our advertising agreement with Yahoo! in June we agreed to delay its implementation until October to give regulators time to look at the details," Google said in an email statement.

"As we are still in conversation with the Department of Justice we have agreed to a brief delay in implementing the agreement while those discussions continue."