UNITED NATIONS - The UN General Assembly opened its 70th session at the UN headquarters in New York late Tuesday, during which the much-anticipated Post-2015 Global Development Agenda will be adopted at a summit from Sept 25-27.

"It is a great honour for me to open the 70th session, a session which I hope will be truly historic," Mogens Lykketoft of Denmark, president of the UN General Assembly, said in his opening address.

Lykketoft was elected to the current post by the UN General Assembly on June 15. At the time of his election, Lykketoft was the Speaker of the Danish Parliament, a position he has held since 2011.

"In less than 10 days' time, our leaders will gather in this hall to adopt the 2030 Agenda for Sustainable Development," he added.

More than 150 heads of state and government, including Pakistan Prime Minister Nawaz Sharif, will attend the 70th anniversary session.

"In signing up to the 2030 Agenda, governments will voluntarily commit to take action for the dignity, security, prosperity and human rights of our shared humanity, for gender equality and the empowerment of women and girls; for the sound management and fair distribution of the Earth's finite resources, and for the health and vitality of our planet," he said.

"The challenge now, and a major priority for my Presidency, is to ensure that all actors move swiftly to deliver on the promises being made," Lykketoft added. UN Secretary-General Ban Ki-moon also spoke at the opening of the 70th session. "This session marks the 70th anniversary of the founding of the United Nations. The Charter's principles have stood the test of time, and the United Nations can look back on a record of achievement," Ban said.

"At the same time, we know that suffering remains widespread across the world. My thoughts today are especially with the people of Syria -- those inside the country facing terrible violence, and those who have fled, desperately seeking a safe haven and a better life," Ban said.

The secretary-general also noted a number of major milestones on the 2016 calendar. In April, the High-level Thematic Debate of the General Assembly on the World Drug Problem is expected to take place. "I encourage Member States to arrive at common solutions on how to address this threat to people and communities," Ban said.

In May, the World Humanitarian Summit in Istanbul comes at a time when nearly 60 million people have been displaced by conflict and violence -- more than at any other time since World War II, Ban said. "Your leadership is critical to make the changes that are needed to address pressing humanitarian challenges and build a safer world for all. I urge you to continue to give the Summit process your full support," Ban said.

Tuesday's opening of the session will be followed, in the second week, by the United Nations summit to adopt the Post-2015 Development Agenda. World leaders are expected to agree to a new set of sustainability measures that build on the successes of, and lessons learned from, the landmark Millennium Development Goals (MDGs) -- the United Nations' anti-poverty targets that are due to wrap up at the end of 2015, according to the UN website. The assembly's annual general debate, when heads of state and government and other senior national representatives gather to present their views about pressing world issues, will open Sept. 28, and run through Oct. 5.

Made up of all the 193 member states of the United Nations, the General Assembly provides a forum for multilateral discussion of the full spectrum of international issues covered by the UN Charter. It meets in regular sessions from September to December each year, and thereafter as required.