At least nine Palestinians have been killed by Israeli forces in the north of the occupied West Bank, Palestinian health officials say.
However, the true figure could be higher, with Palestinian officials earlier saying that at least 11 people had been killed since the Israeli operation began at midnight local time.
Israeli security forces said they were carrying out "a counterterrorism operation to thwart terror" in Jenin and Tulkarm.
This appears to be a major Israeli operation, with at least four Palestinian cities being targeted at the same time – Jenin, Tulkarm, Nablus and Tubas.
Israeli forces conduct regular raids in the West Bank but this one seems more far-reaching than most.
It is believed to be the first time since the second intifada – a major Palestinian uprising from 2000 to 2005 – that several Palestinian cities have been targeted simultaneously in this way.
The West Bank is a chunk of land located on the west bank of the River Jordan and bounded by Israel to the north, west and south. To its east lies Jordan.
It has been occupied by Israel since the 1967 Middle East war, but decades of difficult on-off talks between Israel and the Palestinians – both of whom assert rights there – have left its final status unresolved.
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