Both the Red Crescent and the health ministry in Gaza said protesters were injured by tear gas, rubber bullets and live fire.
Thousands of people demonstrated in various parts of the West Bank, occupied since 1967 by the Israeli army, and near the security barrier that seals off the Gaza Strip, AFP journalists said.
For more than 10 years, the coastal territory of Gaza has been under a rigorous Israeli blockade designed to contain the Hamas Islamist movement which controls it.
Gazans regularly challenge Israeli soldiers guarding the concrete and metal barrier that separates it from the Jewish state.
Hundreds of Gazans waving Palestinian flags approached the barrier today and threw stones and burned tyres, photographers said.
The health authorities in the enclave said eight people were wounded by bullets and around 30 suffered the effects of tear gas inhalation.
In the southern West Bank, around 1,500 people protested in Hebron, and clashes were also reported in other towns and villages.
The Palestinians were demonstrating in support of hundreds of prisoners in Israeli jails who have been on hunger strike since April 17, demanding better conditions.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)