United Nations Secretary-General Antonio Guterres warned on Thursday against scrapping an international deal on Iran's nuclear program, calling US President Donald Trump to stick with the deal. 

Guterres said the deal was an important achievement and a diplomatic victory that must be preserved. It should not be scrapped, he added, unless there was a better alternative.

The UN chief made this remark in an interview with BBC Radio 4, as Trump is reportedly poised to scrap the agreement ahead of a May 12 deadline for Washington to renew its support for the deal.

"I believe the JCPOA (the Iran nuclear deal) was an important diplomatic victory and I think it will be important to preserve it but I also believe there are areas in which it will be very important to have a meaningful dialogue because I see the region in a very dangerous position," he said.

"I understand the concerns of some countries in relation to the Iranian influence in other countries of the region. So I think we should separate things."