NEW YORK: The US President, Mr Barack Obama and his wife Ms Michelle Obama along with former president, Mr George Bush and his wife Ms Laura Bush led the world in mourning the loss of nearly 3,000 people, who lost their lives exactly 10 years ago in the most fearful terror attack that changed the way we live.

Dressed in black, the two couples held hands as they walked slowly along the memorial, watching the wall etched with names of the 2,983 people killed in the terror unleashed by now slain Al-Qaeda chief, Osama bin Laden.

Even though bin Laden was taken out in unilateral raid by American military commandos on May 2 in Pakistan, the wounds of the victim’s families, including Indians, remained fresh.

An eerie silence gripped the Ground Zero as the America’s first family along with Mr Bush spent about a minute at the 30-foot waterfalls that are part of the new memorial.

People silently held on to American flags as well as photos of their loved ones who died when hijacked twin planes rammed into the iconic World Trade Centre here, bringing the skyscrapers down like a pack of cards.

The ceremony began with a procession of bagpipers and singing of the national anthem by a choir.

Tears rolled down the cheeks of many present as names of the victims were read out at the event, which was under heavy security cover, following fresh security alerts regarding a possible Al-Qaeda attack.

Families could be seen clutching each other’s hand as Mr Obama read out verses from Biblical chapter Psalm 46, which talks about God as a source of refuge and strength.

The mayor, Mr Michael R Bloomberg said the attacks had turned "a perfect blue-sky morning" into "the blackest of nights".

Incidentally, unlike earlier occasions, the ritual of reading the names of the dead took place against a backdrop of the spectacular, three-quarter-built 1 World Trade Centre tower, rather than a construction site – Ground Zero.

People also saw the dedication of a simple, but moving monument consisting of massive fountains, sunk into the footprints of the former towers, with the names of the dead written in bronze around the edges.

People gathered and prayed at cathedrals in their cities and laid roses before fire stations.

Americans saw new memorials in lower Manhattan, rural Pennsylvania and other places.

Formal ceremonies were held in many countries to remember the souls of those killed.

Even though 10 years have passed since the tragic attack, the pain and the suffering still exists.

And it is not that the threat of a terror attack has decreased since then. Even as the world pause to reflect on the tragedy that killed people from more than 90 countries, the city and Washington is under intense security gaze.

Remembrance services were held across Britain for those who died in the attacks, which included 67 Britons.

In London, families of some of the 67 British victims gathered for a service at Grosvenor Chapel and a ceremony was held at St Paul’s Cathedral. Wreaths are to be laid at the September 11 Memorial Garden near the US embassy.

In the first of the global memorials, the US rugby team attended an emotional service in New Zealand, hours ahead of their opening World Cup match against Ireland.

The Australian Foreign Minister, Mr Kevin Rudd and his French counterpart Mr Alain Juppe, laid a wreath to honour those who have fought for freedom at the Australian War Memorial in Canberra.

In Japan, families gathered in Tokyo to pay their respects to the 23 Fuji Bank employees, who were killed in the attack. A dozen of the workers were Japanese.

The South Korean President, Mr Lee Myung-bak sent a letter to US President conveying his "deepest condolences" to the victims of the 9/11 tragedy, their bereaved families and the American public.

Pakistan, which is under pressure to uproot terror safe havens from its soil, pledged to strengthen international cooperation to eliminate terrorism and asked the world community to uphold ideals like tolerance.