Spain is holding a national day of mourning and commemoration Friday, to mark the one year anniversary of the Madrid train bombings which killed 191 people.

Church bells rang out at 7:37 a.m. local time (0637 UTC) to mark the first of 10 explosions that occurred aboard four commuter trains one year ago. The coordinated attacks produced the worst death toll ever from terrorism in Spain.

U.N. Secretary-General Kofi Annan and Morocco's King Mohamed, will join Spanish Prime Minister Jose Luis Rodriguez Zapatero - and the entire Spanish nation - for five minutes of silence at midday.

Islamic militants, predominantly from Morocco and sympathetic to al-Qaeda, claimed responsibility for the attacks.

Some information for this report provided by AFP and Reuters.