sentences:  On 10 December 1942, the Polish Foreign Affairs Minister, Edward Raczyński, addressed the fledgling United Nations on the killings; the address was distributed with the title "The Mass Extermination of Jews in German Occupied Poland".He told them about the use of poison gas; about Treblinka, Bełżec and Sobibór; that the Polish underground had referred to them as extermination camps; and that tens of thousands of Jews had been killed in Bełżec in March and April 1942.One in three Jews in Poland were already dead, he estimated, from a population of 3,130,000.