New York/Washington, Sep 11 (DPA) Mourners in the US gathered Friday to remember the nearly 3,000 people killed in the Sep 11, 2001 terrorist attacks, as the anniversary was proclaimed a national day of service.

In New York, US Vice President Joe Biden and Mayor Michael Bloomberg gathered with families of the victims near the site of the attacks on the World Trade Center's twin towers, known as Ground Zero, on a cold rainy morning and began the ceremony with a minute of silence at 8:46 a.m. to mark the time when the first terrorist-hijacked commercial airplane hit one of the towers.

At the same time, President Barack Obama and his wife Michelle held a minute of silence at the White House. Obama has declared Sep 11 a National Day of Service and Remembrance.

Obama later joined families of the victims for a remembrance service at the Pentagon, which was hit by another hijacked plane that killed 184 people. He laid a wreath at the Pentagon's own memorial.

'We remember with reverence the lives we lost,' Obama said. 'Let us renew our resolve against those who perpetrated this barbaric act and who plot against us still. In defence of our nation, we will never waver.'

Bloomberg joined New Jersey Governor Jon Corzine, family members of the victims and a group of representatives of city departments, including police and firefighters, at Zuccotti Park near the World Trade Center site.