Israel has detained 23 members of Palestinian militant group Hamas in the occupied West Bank.
Three members of parliament were among those arrested, along with several local Hamas leaders.
MPs Ahmed Attoun, Hatem Qafisha and Mohammed al-Talhad were held in early-morning raids across the territory. The Israeli military did not specify the charges.
One of those arrested was in charge of reconciliation talks between Hamas and the rival Fatah.
"It is a criminal act that will not succeed in stopping their struggle," Hamas said. "We in the Hamas movement strongly condemn the campaign of arbitrary arrests that took in dozens of Hamas leaders."
Palestinian human rights group said the arrests were aimed at undermining moves towards reconciliation between the two Palestinian factions.
Israel has held more than 4,500 Palestinians in its jails, according to Palestinian report.
Hamas is considered a terrorist organisation by Israel, the US and the EU, seized control of the Gaza Strip in 2007.
Attempts to reach a reconciliation agreement between Hamas and Fatah, brokered by Egypt, have proved unsuccessful.
A UN fact-finding mission recently urged Israel to stop settlement expansion and withdraw all Jewish settlers from the West Bank, claiming it breaches multiple human rights of the Palestinians.