Tel Aviv, Jan. 18 -- Despite the presence of a Hamas terror tunnel system in the Gaza Strip now thought to be larger in scale than the London Underground, the United Nations insists it had no idea the tunnels were being built.

Asked on Wednesday whether, given the United Nations sizable presence in Gaza via a variety of agencies, there had been any indication to the global body that tunnels were being constructed underground, a spokesman for U.N. Secretary-General Antonio Guterres said, "No is clearly the answer for that."

Spokesman Stephane Dujarric told reporters "it seems to me that all this infrastructure was built in a highly secretive way."

However, officials from the U.N. Relief and Works Agency (UNRWA) sounded the alarm on the ...