Of­fi­cials in some of the 12 coun­tries whose cit­i­zens will be soon banned from vis­it­ing the Unit­ed States de­nounced Pres­i­dent Don­ald Trump’s move to res­ur­rect a hall­mark pol­i­cy of his first term and vowed Thurs­day to push back against the U.S.

The ban, which was an­nounced Wednes­day, takes ef­fect at 12:01 a.m. Mon­day, a cush­ion that may avoid the chaos that un­fold­ed at air­ports na­tion­wide when a sim­i­lar mea­sure took ef­fect with vir­tu­al­ly no no­tice in 2017. Trump, who sig­naled plans for a new ban up­on tak­ing of­fice again in Jan­u­ary, ap­pears to be on firmer ground this time af­ter the Supreme Court sided with him.

The 12 coun­tries — Afghanistan, Myan­mar, Chad, the Re­pub­lic of Con­go, Equa­to­r­i­al Guinea, Er­itrea, Haiti, Iran, Libya, So­ma­lia, Su­dan and Yemen — in­clude some of the world’s poor­est na­tions. Sev­en more coun­tries — Bu­run­di, Cu­ba, Laos, Sier­ra Leone, To­go, Turk­menistan and Venezuela — now face height­ened trav­el re­stric­tions.

In the cen­tral African na­tion of Chad, Pres­i­dent Ma­hamat De­by It­no an­nounced his coun­try would re­spond by sus­pend­ing visas to U.S. cit­i­zens “in ac­cor­dance with the prin­ci­ples of reci­procity.”

In a post on Face­book, De­by not­ed that his na­tion, which faces wide­spread pover­ty, could of­fer no gifts, and he made a bare­ly veiled ref­er­ence to Qatar giv­ing Trump a lux­u­ry Boe­ing 747 jet to use as Air Force One.

“Chad has no planes to of­fer, no bil­lions of dol­lars to give but Chad has its dig­ni­ty and pride,” De­by said.

Some oth­er African coun­tries were more con­cil­ia­to­ry, with Sier­ra Leone’s in­for­ma­tion min­is­ter, Cher­nor Bah, say­ing the coun­try “will work with U.S. au­thor­i­ties” to ad­dress the White House con­cerns.

Some of the 12 coun­tries were on the banned list in Trump’s first term. North Ko­rea and Syr­ia, which were on the list in the first ad­min­is­tra­tion, were spared this time.

While many of the list­ed coun­tries send few peo­ple to the Unit­ed States, Haiti, Cu­ba and Venezuela had been ma­jor sources of im­mi­gra­tion in re­cent years.

Trump tied the new ban to Sun­day’s flamethrow­er at­tack in Boul­der, Col­orado, say­ing it un­der­scored the dan­gers posed by some vis­i­tors who over­stay visas. The sus­pect is from Egypt, which is not on Trump’s re­strict­ed list. The De­part­ment of Home­land Se­cu­ri­ty says he over­stayed a tourist visa.

The trav­el ban re­sults from a Jan. 20 ex­ec­u­tive or­der Trump is­sued re­quir­ing gov­ern­ment agen­cies to com­pile a re­port on “hos­tile at­ti­tudes” to­ward the U.S. and whether en­try from cer­tain coun­tries rep­re­sent­ed a na­tion­al se­cu­ri­ty risk.