The whole world has responded to the bomb attacks in Spain vigorously. For Europe, rumors say London, France, Italy, Germany and some other important countries are at high risk to become the next bomb target.

Under the midst of hidden disastrous danger, Europeans across the continent expressed their deepest sorrow for the victims in the Spain bomb attack in various ways.

The Europe-wide mark of respect was initiated by the president of the European Council, Irish premier Bertie Ahern, who called on all EU member states to mark the silence in solidarity with the Spanish people.

From airports to car plants, schools to government ministries, all Europeans stopped work for three minutes of silence Monday to honor the dead in last week's Madrid trains blasts.

At 11: 00 am GMT, in the heart of Europe, London's Heathrow, all flights going to set off and immigration counters are stopped for 3 minutes to avoid disturbing the silence.

While the peace talks held between Turkish and Greek in Cyprus, mediators suspended the negotiation to observe the silence.

It seemed that the only sound came from the bells of churches across Europe. In Berlin, bells of the Gedaechtniskirche church partly ruined in the World War II, chimed with a heavy and long expressing its deepest blessing to the Spanish victims.

Behind the peaceful silence, each national security department in Europe is in the wake of preparing higher defensive actions for the risk of bomb attack, especially London, where is considered to be the most dangerous location.

Plain clothes anti-terrorist police patrolled in London underground. Deputy Chief Constable (DCC) Andy Trotter of the British Transport Police said, "the threat from terrorism remains very real, as the events in Madrid show. London is on a high level of alert."

Irish prime minister announced Monday the European Union will hold high-level security talks on Friday to assess what additional anti-terrorism measures to take in the wake of the bombings in Madrid, as demanded by Germany Interior Minsiter Otto Schily last Saturday.

Many speculated on the identity of the bombers. Jean-Philippe Miginac, publisher of Strategic Road, an internet site specializing in strategic intelligence commented there were certainly links with the Islamic terrorist groups.