Israel has barred 30 runners, including an Olympic athlete, from leaving the Gaza Strip to participate in a marathon today, highlighting its tight restrictions on travel in and out of the Hamas-ruled territory.

In the case of the Olympic runner Nader Masri, the travel ban was upheld on Tuesday by Israel's Supreme Court. Masri, 34, participated in the 2008 Olympics in Beijing.

The case underscored Israel's restrictions on Gaza, which human rights activists argue amount to collective punishment and are often arbitrary. They say the travel ban is part of an Israeli attempt to sever ties between Gaza and the West Bank, territories that lie on opposite ends of Israel and along with east Jerusalem are the basis of any future Palestinian state.