U.N. Secretary-General Ban Ki-moon stands behind Chinese President Xi Jinping on Saturday as Xi signs the guest book to attend a global summit at U.N. headquarters. (AP / BRYAN R. SMITH )

UNITED NATIONS -- China's president on Saturday pledged billions in aid and said Beijing will forgive debts due this year in an effort to help the world's poorest nations, as world leaders begin to seek the trillions of dollars needed to help achieve sweeping new development goals.

President Xi Jinping spoke at a global summit that on Friday launched the nonbinding goals for the next 15 years.

The U.N. gathering began to shift focus from development to the General Assembly meeting that begins Monday with speeches by Xi, President Barack Obama, Russian President Vladimir Putin and Iranian President Hassan Rouhani on the first morning alone.

Obama and Putin will meet Monday. The prospects for any meeting between Obama and Rouhani, even a handshake, remained unclear.

Rouhani arrived Saturday and immediately was encouraged by U.N. Secretary-General Ban Ki-moon to have Iran step up to help achieve political settlements in the ongoing conflicts in Syria and Yemen, where Iran has influence. The Islamic republic is a top ally of the Syrian government of President Bashar Assad and supports Shiite Houthi rebels who have held parts of Yemen for months.

Iran's president said in his address that the recent deal with world powers on its nuclear program "has created suitable conditions for regional and international cooperation," including collaboration on protecting the environment.

As world leaders met behind the scenes, others lined up to express support for the development push that aims to eliminate both poverty and hunger over the next 15 years. They replace a soon-to-expire set of development goals whose limited success was largely due to China's surge out of poverty over the past decade and a half.

The goals include ensuring "healthy lives" and quality education for all, clean water, sanitation and reliable modern energy, as well as making cities safe, reducing inequality within and among countries, and promoting economic growth and good governance.

Critics said the goals are too broad, lack accountability and will lead to disenchantment among those most in need of hope.

Supporters said there is no choice but to aim high in a world of expanding population, growing inequality, dwindling resources and the existential threat of global warming. They noted that while the millennium goals were developed by then secretary-general Kofi Annan and his staff, the new goals are the result of years of negotiations by all 193 member states, which means they should all have a stake in their achievement.

Sweden announced that a group of nine leaders from different regions will work to ensure implementation of the goals. It includes German Chancellor Angela Merkel, the presidents of Brazil, Colombia, Liberia, South Africa, Tanzania and Tunisia and the prime ministers of Sweden and East Timor.

China's president vowed to help other countries make the same transformation. Xi said China will commit an initial $2 billion to establish an assistance fund to meet the post-2015 goals in areas such as education, health care and economic development. He said China would seek to increase the fund to $12 billion by 2030.

And Xi said China would write off intergovernmental interest-free loans owed to China by the least-developed, small island nations and most heavily debt-burdened countries due this year.

He said China "will continue to increase investment in the least-developed countries," and support global institutions, including the Beijing-backed Asian Infrastructure Investment Bank that is due to open by the end of the year and is seen as a Chinese alternative to the more Western-oriented financial institutions of the World Bank.

Ban made a major pitch to the private sector Saturday for its help in financing the development goals.

"In a sense, Sept. 26 is even more important than Sept. 25," he told dozens of global business leaders from companies including Google, Unilever, Siemens and Sinopec. "Today, we begin the hard work of turning plans into reality."

Information for this article was contributed by Christopher Bodeen and Edith M. Lederer of The Associated Press.

A Section on 09/27/2015