U.S. President Donald Trump (R) greets Samuel Zeif, a student of Marjory Stoneman Douglas High School before a listening session on school safety at the White House in Washington D.C., the United States on Feb 21, 2018. U.S. President Donald Trump promised strong background checks and mental health screenings for gun buyers as he heard pleas from survivors of the recent Florida school shooting and families affected at the White House on Wednesday. (Xinhua/Ting Shen)