GABORONE, Dec 3 (Reuters) - Botswana"s President Mokgweetsi Masisi said some of the four diplomats who first tested positive for the Omicron coronavirus variant in the country had come from Europe, calling for a reversal of widespread travel bans imposed against southern African countries. Omicron, dubbed a variant of concern by the World Health Organization, has prompted many governments to impose curbs on travel from southern Africa, and to take other measures to contain it. While it is still not established where Omicron first emerged, on Nov. 25 South Africa, followed by Botswana a day later, announced they had detected a new variant whose mutations were different from the dominant Delta variant. South Africa has also complained it is being punished for having identified the new variant early. "It is unnecessary and if you ask me, for lack of a better expression, irresponsible," Masisi said of the travel curbs, speaking in an interview with CNN on Thursday evening. "The diplomats came from a number of countries ... and they passed through a number of countries to get to Botswana." He declined to disclose their nationalities, only saying "some had been to Europe and some had been elsewhere". Asked if some had come from Europe into Botswana, he replied "indeed". Botswana said last week the country was investigating certain mutations of the coronavirus that were found in four foreign nationals who were in the country on a diplomatic mission. Omicron was detected in the diplomats who travelled into country on Nov. 7 and left on Nov. 11. read more The country has so far reported more than 20 cases of the new variant. Presidential spokesman Batlhalefi Leagajang told Reuters on Friday that Masisi will not disclose the countries the diplomats passed through, or their countries of origin, because "the virus should never be geo-politicized." Omicron has been reported in at least two dozen countries. (This story has been refiled to fix variant spelling in headline)