JERUSALEM - The Tel Aviv Stock Exchange has delayed the start of the week's first session after pre-opening trade showed the benchmark index dropping more than 6 percent following the downgrading of the United States' debt rating.

Exchange spokeswoman Idit Yaaron said the start was pushed back by 45 minutes "so market players will have time to react logically and not under pressure."

Credit rating agency Standard & Poor's downgraded the US's rating late Friday by one notch, from the sterling AAA to AA+. The cut is expected to reverberate across world markets.

The Israeli exchange's TA-25 blue chip index fell as much as 6.5 percent in pre-opening activity.

The exchange operates on a Sunday through Thursday schedule, and is one of the first worldwide to react to the ratings cut.