The Palestinian National Authority (PNA) on Monday opened an investigation into clashes between demonstrators and police in the West Bank city of Ramallah.

At least 15 people were injured, including six journalists, when the PNA forces repressed demonstrations Sunday and Saturday when protestors called on President Mahmoud Abbas not to receive Israeli Deputy Vice Premier Shaul Mofaz in Ramallah.

Mofaz's visit has been canceled.

The PNA will take "necessary procedures" according to the conclusions of the investigation committee, the PNA interior ministry said in a statement.

Meanwhile, Abbas pledged to curb any violation of the freedom of expression and demonstration in the Palestinian territories.