Eritrea and Kyrgyzstan have denounced US President Donald Trump's controversial travel ban which targets prospective immigrants from six additional countries.

Eritrean Foreign Minister Osman Saleh Mohammed said on Saturday that the government saw the ban as a political move that would hurt the country's relations with the US.

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"We find this move unacceptable," he told Reuters news agency by telephone. "We will, however, not expel the US ambassador," Mohammed said.

Kyrgyzstan hit out on Saturday at the immigration restrictions that will apply to its nationals, stating that they had been applied selectively and had damaged relations.

The two countries were among six that were added to an expanded version of the US visa ban, announced on Friday in a presidential proclamation.

Under the proclamation, which will take effect on February 21, the US will suspend the issuance of visas that can lead to permanent residency for nationals of the affected countries.

Immigrants from Nigeria and Myanmar will no longer be eligible for visas allowing them to live in the US permanently, while citizens from Sudan and Tanzania will not be eligible to enter a lottery to apply for immigrant visas.

'We don't have official communication'

Nigeria's government said it had created a committee to address the issues that prompted the ban, while Tanzania said it had not been officially notified by the US about the travel ban.

"Nigeria remains committed to maintaining productive relations with the United States and other international allies especially on matters of global security," a Nigerian presidential statement said.

Nigeria's information minister Lai Mohammed told Reuters they had no warning of their inclusion on the list before it appeared in the media.

Emmanuel Buhohela, spokesman for the Tanzanian ministry of foreign affairs said: "We don't have official communication from the US government. We haven't received a formal diplomatic communication, which is the official way of communicating between governments."

Acting Homeland Security Secretary Chad Wolf told journalists the visas affected are distinct from non-immigrant visitor visas, which will not be impacted by the ban.

Immigrant advocates and rights groups have also slammed the expansion of the controversial travel ban, saying it weaponises "immigration law to advance [the administration's] xenophobic agenda".

The original travel ban - issued during Trump's first week in office in January 2017 - barred nearly all immigrants and travellers from seven Muslim-majority nations. It caused widespread outrage and chaos at airports across the US.

The policy was revised amid court challenges, but the US Supreme Court ultimately upheld it in June 2018.

The existing version of the ban includes the Muslim-majority nations of Iran, Libya, Somalia, Syria and Yemen. North Korea and Venezuela also face visa restrictions, but those measures affect relatively few travellers.