Take this with a grain of salt (especially when reading this in articles sourced from Pakistan or Saudi news agencies).
I know that in one such instance, the "Israelis" that were arrested in the US were not Jewish, but "Palastinian" Israeli citizens. By not stating the religious or ethnic background of the Israeli, the Pakistanis and Saudis have been implying that it was actually Jews, not muslims, who carried out the terrorist activity. In some parts of the world (including among some tinfoil crowds in the US) the real culprits have not even been identified yet and "muslims" are being blamed unjustly.
Whether "Israelis" were involved in terrorist activity in the US or not has no relation to whether Israeli intelligence had foreknowledge about the Islamic attacks planned for September 11th. So far, I have not seen credible evidence of that either.