Aziz Dweik, also a key member of Hamas, which controls the government, was held after 20 Israeli vehicles surrounded his home in Ramallah. The Israeli military confirmed the detention, saying Mr Dweik was a legitimate target as a Hamas leader. Palestinian Prime Minister Ismail Haniya condemned the action, accusing Israel of "piracy".
He said: "We urge all Arab and international parliamentarians to condemn and denounce this crime and to secure the release of Aziz Dweik and all jailed ministers and lawmakers." Israel detained eight members of the Hamas-led government and 20 MPs on 29 June. Palestinians called that an act of war. The detentions followed the capture of an Israeli soldier by Palestinian in June.
Sixty-four other leading members of the Islamist movement, including eight ministers and 26 other politicians were also detained on June 29. They were grabbed as part of a massive Israeli sweep against Hamas following the capture of an Israeli soldier by fighters on the border of the Gaza Strip on June 25.
Dweik's wife said that Israeli troops also seized two computers and documents of the Palestinian parliament when they arrested her husband. Saeb Erikat, the Palestinian chief negotiator, condemned the arrest and demanded that Dweik and the other detainees be released. Dweik was elected speaker in February.
He had previously been arrested five times by Israeli authorities, and was also part of a group of 400 Palestinians who were banned by
Earlier on Saturday, five more Palestinians, including two fighters, were killed in the Rafah area by Israeli missiles. Medics said the Palestinian killed in the latest air raid was a civilian and that four others were wounded. Late on Saturday a Palestinian boy was killed in an air strike in the southern town of Rafah, local medical sources said. Earlier, at least four people - two civilian teenagers - died in separate Israeli attacks in the area.
The Israeli army had no immediate comment.