World leaders are converging on New York this week for the United Nations General Assembly. Syria is expected to dominate much of the debate.
United States President Barack Obama is due to speak to the General Assembly on Tuesday.
Security at the UN has tightened for this week, with about 160 leaders expected to attend.
The whole area is fenced off for blocks around the UN buildings, causing further congestion in New York.
People can move in and out of the area only if they have accreditation and police officers and Secret Service agents patrol the perimeter.
On the other side of the UN, gun boats patrol the Hudson River.