UN Secretary-General Antonio Guterres on Tuesday sharpened his criticism of the US ban on travellers from seven Muslim nations, saying such "blind measures' are unlikely to be effective in fighting terrorism.

Guterres said countries seeking to strengthen control of their borders cannot do so "based on any form of discrimination related to religion, ethnicity or nationality."

Such discrimination "triggers widespread anxiety and

anger that may facilitate the propaganda of the very terrorist organizations we all want to fight against," Guterres said in his first statement on the controversy.

On Friday, President Donald Trump signed an executive order suspending the arrival of all refugees for a minimum of 120 days, Syrian refiigees indefinitely, and barring citizens from Iran, Iraq, Libya, Somalia, Sudan, Syria and Yemen for 90 days.

The decision triggered protests and chaos at airports while UN human rights chiefZeid bin Ra'ad Zeid al-Hussein declared it illegal and "mean-spirited."

*Blind measures, not based on solid intelligence, tend to be ineffective as they risk being bypassed by what are today sophisticated global terrorist movements," said Guterres.

Guterres earlier said through his spokesman that he hoped the US measure was temporary, but did not condemn it, nor did he urgeTrump to reverse course.

In the statement released Tuesday, Guterres did not explicitly mention the US ban, but there was no doubt his statement was a response to the controversial measure.

He said he was concerned by decisions around the world that are undermining international refugee protection.

"This is against the fundamental principles and values on which our societies are based," said the UN chief.

On Monday, Human Rights Watch had called on Guterres to clearly denounce the ban.

"At a time when governments, civil society and business leaders are increasingly speaking out, it's important that the UN's message not come solely from the UN human rights chief," said HRW deputy director for global advocacy Philippe Bolopion.

“Secretary-General Guterres should take a clear stand that Trump's executive order is a blow to refugees, reflects bigotry and will do little to address terrorism."