UN Secretary-General Antonio Guterres says Iranian nuclear deal is "very important and it should be maintained". 

UN spokesman Stephane Dujarric in a statement said the Secretary General believes "We must build on this important achievement to preserve the non-proliferation regime which is a cornerstone of our global security."

Antonio Guterres also met with Iranian Foreign Minister Mohammad Javad Zarif and discussed Iran's nuclear program in exchange for sanctions relief.

Meanwhile, the UN Secretary General Antonio Guterres will appoint its Swiss ambassador to Germany, Christine Schraner Burgener on Thursday as his new special envoy to Myanmar. 

Earlier, UN General Assembly in December asked Guterres to appoint a special envoy to end its military campaign in Rakhine state.