Police arrested eight Greenpeace activists Thursday after members of the group chained themselves to a bridge in Jerusalem demanding US President Barack Obama halt exploratory drilling in the Arctic, an official said.

"We have taken in eight activists for questioning, but there are still others at the site," police spokesman Micky Rosenfeld told AFP.

Earlier, several activists wearing white overalls and yellow helmets used climbing gear to scale Jerusalem's soaring Bridge of Strings, inching up the metal cables which span a busy intersection at the entrance to the city.

"Obama: Stop the drilling in the Arctic" read a sign in Hebrew unfurled by the protesters climbing the structure, which at 119 metres (390 feet), dominates the Jerusalem skyline.

The protest came a day after Obama began his first official visit to Israel since first being elected president more than four years ago.

Designed by Spanish architect Santiago Calatrava, the bridge has 66 "strings" which are connected to a single towering cantilevered mast in a design resembling the harp of the biblical King David.

It is located at the city's western entrance over the main road leading to Tel Aviv.

There are 5,000 police on duty in Jerusalem every day of the US presidential visit, but officers initially appeared unable to halt the high-profile stunt, an AFP correspondent said.

Last year, the environmental group launched a Save The Arctic campaign to preserve the land mass from oil exploration and industrial fishing.

According to the US Geological Survey, the Arctic is believed to hold 13 percent of the planet's undiscovered oil reserves and 30 percent of its undiscovered natural gas.