Forty Palestinians and an Israeli were wounded as occupation troops fired teargas and rubber bullets to break up a protest close to the controversial barrier.
Israeli police said four Israelis were also arrested at the protest near the Palestinian village of Budrus, near Jenin in the northern West Bank.
Israeli soldiers arrested Gustav Fridolin, a Swedish member of parliament who was among a group of protesters detained near the village.
It was the second protest in five days against the separation wall which Israel claims is needed to keep prevent resistance fighters from carrying out bomb attacks inside Israel.
The wall has been criticised internationally because parts of the barrier made of concrete, razor wire, and trenches snakes through Palestinian land.
Palestinian demonstrators shout
at Israeli border police in Budrus
Gil Kleiman, a spokesman for Israeli national police, said "a decision was made to deport all four of the foreigners detained today," including the Swedish lawmaker named by Sweden's embassy in Tel Aviv as Gustav Fridolin of the Greens Party.
All four were expected to appeal the decision to a board on Thursday and would remain in custody pending a decision.
Anna Weekes, a protester from South Africa, said Fridolin had been detained by soldiers as he sang pro-Palestine songs with a group of local schoolchildren.
"We were sitting on a terrace singing 'Free, Free Palestine'. Then they grabbed various internationals," she said.
"They have taken him and the others away to a detention centre." Protesters added that an Israeli, Nimrod Kerreet, had been beaten by soldiers who were trying to arrest him.
An Israeli military source said seven people had been arrested for trying to block work for the barrier.
Around forty Palestinians were
injured at the large demonstration
"A few protesters came to the place at Budrus where there was engineering work. They came and protested in a controlled manner.
"Then at some stage they started to prevent the work, by standing in front of the vehicles, blocking the road," the military spokesperson added.
Israel has deported dozens of peace protesters accused of involvement in "illegal activities" in the West Bank and Gaza Strip. This includes internationals and Israeli nationals who enter Palestinian areas whilst occupation troops are invading towns or cities, and activists who assist Palestinian farmers in harvesting olives.
It's much less common for Israel to deport foreign politicians or diplomats.
Expelled to Gaza
Israel expelled a Palestinian from the West Bank to the Gaza Strip after accusing him of belonging to armed resistance group, Islamic Jihad.
Palestinian officials said Mustafa Abed, a 40-year-old father of seven from the West Bank city of Nablus, was taken to the Gaza Strip by Israeli occupation troops late on Wednesday.
Palestinian officials and international human rights groups have condemned Israel for using the measure against Palestinians, saying such expulsions are a violation of international law.
An Israeli military spokesperson confirmed that Abed had been expelled to Gaza for a period of two years as "preventive measure".
Abed told the Reuters news agency that he had been arrested by Israeli occupation troops more than a year ago and held in custody without charge.