Obama delivers maiden UN address

US President Barack Obama is delivering his first speech to the United Nations General Assembly in New York.
He is expected to say the US is acting to tackle global challenges, but will stress that other nations also need to do their part.
Mr Obama will also stress the change in attitude of the US to the UN compared with that of the Bush administration.
The assembly will also hear from Libyan leader Col Muammar Gaddafi for the first time, and the Iranian president.
Relatives of victims of the 1988 Lockerbie bombing protested outside the UN headquarters as Col Gaddafi was due to arrive. The Libyan convicted of the bombing was released from a Scottish prison last month.
MARDELL'S AMERICA

It sounds as though President Obama is going to climb into the bully pulpit and call on other nations to match the level of US commitment
Mark MardellBBC North America editor
Read Mark's thoughts in full
Iranian President Mahmoud Ahmadinejad, who has previously said he does not believe the Holocaust happened, is due to speak later in the day.
Israel has called for a boycott of his appearance and the Germans have said they will walk out if he repeats the claim.
Mr Obama is addressing leaders from more than 120 countries, a day after he spoke at the UN's climate change summit.
The president acknowledged that the US had been slow to act, but promised a "new era" of promoting clean energy and reducing carbon pollution.
His maiden general assembly speech will address nuclear non-proliferation, "peace and security, climate change, and global growth and development, and underscore America's fundamental commitment to universal values - and challenge others in the United Nations to do the same", an unnamed senior US official said.
UN SPEECHES ON WEDNESDAY
1300 GMT - General debate
1330 - US President Obama
1345 - Libyan Col Gaddafi
1715 - UK Prime Minister Brown
2015 - Russian President Medvedev
2130 - Iranian President Ahmadinejad
UN Assembly: Key Issues
Big week for Obama at UN
Gaddafi protest planned
Some countries may not take kindly to his words urging greater responsibility if it sounds too much like a lecture, particularly those who feel his commitments to tackle global warning were disappointing, says the BBC's Mark Mardell in New York.
UN Secretary General Ban Ki-moon opened Wednesday's proceedings by telling the assembled leaders: "Now is the time to put the 'united' back into the United Nations".
He outlined problems facing the world - including "catastrophic climate change", the proliferation of nuclear weapons, and the global economic crisis - and said the world was looking to the UN for answers.
"We must act for all nations and all people. So much is possible if we work together. We are the UN, the best hope for humankind, and now is our time," Mr Ban said.
SPEAKER PROTOCOL
By tradition dating back to the UN's infancy in the late 1940s, Brazil speaks first after the secretary general opens proceedings
The US, as host country, speaks second
Subsequent speakers are chosen on a first-come, first-served basis
Protocol order is followed: heads of state; heads of government; crown princes; deputy prime ministers; ministers; permanent representatives
However, the order can change up till the last moment
The order of the speeches is based on protocol, with some flexibility.
A UN spokeswoman described it as a "challenging and meticulous" task to decide the order.
There is an agreed order of hierarchy - with heads of state coming before heads of government and crown princes.
But exceptions are made - this time UK Prime Minister Gordon Brown will speak before China's head of state, President Hu Jintao.