New York Governor Andrew Cuomo,(L) looks on as New York City Mayor Bill de Blasio(2nd-L) speaks with NYC OEM Commissioner Joseph Esposito(C) near the scene of an explosion on West 23rd Street September, 18, 2016 in New York. An explosion rocked one of the most fashionable neighborhoods of New York on September 17 night, injuring 29 people, one seriously, a week after America's financial capital marked the 15th anniversary of the 9/11 attacks. Mayor Bill de Blasio indicated the blast was not accidental, even if there was no known link to terrorism. The blast occurred in Chelsea -- an area packed with bars, restaurants and luxury apartment blocks -- at a typically bustling time of the weekend. / AFP PHOTO / Bryan R. SmithBRYAN R. SMITH/AFP/Getty Images

Berlin's mayor Michael Mueller (R), top candidate of the social democratic SPD party, addresses the audience as (L-R) German Family Minister Manuela Schwesig, German Vice Chancellor, Economy and Energy Minister and SPD leader Sigmar Gabriel and his wife Claudia Mueller (2ndR)look on during their electoral evening in Berlin after a regional election on September 18, 2016 in Berlin. Some 2.5 million eligible voters in Berlin will choose both a new city-state parliament and 12 local district assemblies. / AFP PHOTO / Odd ANDERSENODD ANDERSEN/AFP/Getty Images

New York City Mayor Bill de Blasio walks near near the scene of an explosion on West 23rd Street September, 18, 2016 in New York. An explosion rocked one of the most fashionable neighborhoods of New York on September 17 night, injuring 29 people, one seriously, a week after America's financial capital marked the 15th anniversary of the 9/11 attacks. Mayor Bill de Blasio indicated the blast was not accidental, even if there was no known link to terrorism. The blast occurred in Chelsea -- an area packed with bars, restaurants and luxury apartment blocks -- at a typically bustling time of the weekend. / AFP PHOTO / Bryan R. SmithBRYAN R. SMITH/AFP/Getty Images

German Vice Chancellor, Economy and Energy Minister and SPD party leader Sigmar Gabriel addresses the audience next to Berlin's mayor Michael Mueller (R), top candidate of the social democratic SPD party, during their electoral evening in Berlin after a regional election on September 18, 2016 in Berlin. Some 2.5 million eligible voters in Berlin will choose both a new city-state parliament and 12 local district assemblies. / AFP PHOTO / Odd ANDERSENODD ANDERSEN/AFP/Getty Images

New York Governor Andrew Cuomo,(R) and New York City Mayor Bill de Blasio take a walk near the scene of an explosion on West 23rd Street September, 18, 2016 in New York. An explosion rocked one of the most fashionable neighborhoods of New York on September 17 night, injuring 29 people, one seriously, a week after America's financial capital marked the 15th anniversary of the 9/11 attacks. Mayor Bill de Blasio indicated the blast was not accidental, even if there was no known link to terrorism. The blast occurred in Chelsea -- an area packed with bars, restaurants and luxury apartment blocks -- at a typically bustling time of the weekend. / AFP PHOTO / Bryan R. SmithBRYAN R. SMITH/AFP/Getty Images

New York Governor Andrew Cuomo(R) and New York City Mayor Bill de Blasio(L) greet investigators near the scene of an explosion on West 23rd Street September, 18, 2016 in New York. An explosion rocked one of the most fashionable neighborhoods of New York on September 17 night, injuring 29 people, one seriously, a week after America's financial capital marked the 15th anniversary of the 9/11 attacks. Mayor Bill de Blasio indicated the blast was not accidental, even if there was no known link to terrorism. The blast occurred in Chelsea -- an area packed with bars, restaurants and luxury apartment blocks -- at a typically bustling time of the weekend. / AFP PHOTO / Bryan R. SmithBRYAN R. SMITH/AFP/Getty Images

New York Governor Andrew Cuomo,(R) and New York City Mayor Bill de Blasio take a walk near the scene of an explosion on West 23rd Street September, 18, 2016 in New York. An explosion rocked one of the most fashionable neighborhoods of New York on September 17 night, injuring 29 people, one seriously, a week after America's financial capital marked the 15th anniversary of the 9/11 attacks. Mayor Bill de Blasio indicated the blast was not accidental, even if there was no known link to terrorism. The blast occurred in Chelsea -- an area packed with bars, restaurants and luxury apartment blocks -- at a typically bustling time of the weekend. / AFP PHOTO / Bryan R. SmithBRYAN R. SMITH/AFP/Getty Images

New York Governor Andrew Cuomo(R) and New York City Mayor Bill de Blasio(L) greet investigators near the scene of an explosion on West 23rd Street September, 18, 2016 in New York. An explosion rocked one of the most fashionable neighborhoods of New York on September 17 night, injuring 29 people, one seriously, a week after America's financial capital marked the 15th anniversary of the 9/11 attacks. Mayor Bill de Blasio indicated the blast was not accidental, even if there was no known link to terrorism. The blast occurred in Chelsea -- an area packed with bars, restaurants and luxury apartment blocks -- at a typically bustling time of the weekend. / AFP PHOTO / Bryan R. SmithBRYAN R. SMITH/AFP/Getty Images