Standard & Poor’s cut Egypt’s rating on Tuesday by one notch, following similar actions by Moody’s and Fitch Ratings. But S&P went a step further, saying it would cut the nation’s rating again, and by a larger margin, within three months if the current political instability continues.

Reuters reported that S&P cited the public unrest and demonstrations as endangering Egypt’s growth and wreaking havoc with its public finances, even as citizens seek to drive President Hosni Mubarak from office. With that in mind, the company changed its outlook on both long-term foreign and local currency ratings to negative, and dropped the former to BB and the latter to BB+.

In a statement, the company also said, “We may lower the ratings again, potentially by more than one notch, within the next three months if we see further significant instability in the political environment.”

Both Fitch and Moody’s, which cut Egypt’s ratings on Friday and Monday, respectively, also cited the protests as the cause for their actions.  Fitch said that the reason was that unrest would undermine economic reforms and Moody’s said it was out of concern over the possibility of Cairo seeking to assuage the protestors by increasing its social spending. Fitch dropped its outlook on the country rather than its rating; Moody’s lowered the country’s rating from Ba1 to Ba2.

Worries over Egypt, as well as other political turmoil in North Africa, are causing ratings agencies more concern about long-term effects. Meanwhile, Egypt’s banks are due to be shuttered again on Wednesday, according to the nation’s central bank, with the decision still unmade about whether they will reopen on Thursday. The stock exchange will also remain closed on Wednesday. British banking firm Barclays (BARC.L), which has 65 branches in Egypt, said on Tuesday that, following advice from the Egyptian central bank, it has ordered all its offices there closed.