The European Union (EU) and Russia on Tuesday called for a full and impartial inquiry into the Israeli attack on a Gaza-bound international aid flotilla.

The EU and Russia "demand a full and impartial inquiry of the events and circumstances," said a declaration issued by Russian Foreign Minister Sergei Lavrov and EU foreign policy chief Catherine Ashton.

Israel's operation on Monday had triggered widespread criticism from countries and international organizations around the world.

"The EU and Russia call for immediate opening of crossings for the flow of humanitarian aid, commercial goods and people to and from Gaza," said the declaration issued at a two-day Russia-EU summit.

Later at the joint press conference, both Russian President Dmitry Medvedev and EU Council President Herman van Rompuy reiterated their condemnation at the attack and urged a thorough, unbiased investigation into the inquiry.

"It is necessary to perform an extremely thorough investigation ...However, in any case, the deaths of people are irreversible and absolutely unmotivated," said Medvedev.

Van Rompuy, who expressed his "sincere condolences" over the tragic incident, said the declaration by Lavrov and Ashton had his full support on behalf of the 27-member European bloc.

He also condemned the use of violence, called for "full, immediate and impartial" inquiry into the incident as well as the "immediate opening of crossings" to and from Gaza.

At least 10 people were killed and some 30 injured in the predawn clash between Israeli navy and pro-Palestinian activists on board the ships loaded with supplies of cement, water purification systems and wheelchairs.

The incident happened after Isreali soldiers tried to stop the flotilla from reaching besieged Gaza. The Israeli army said their commandos opened fire at the ships when they felt their lives were "under threat."