WASHINGTON -- Vancouver Mayor Gregor Robertson has trashed the Harper government's record on climate change in front of a distinguished audience at the U.S. State Department.

His comments came during a conference on green cities, organized by former New York mayor and current UN climate envoy Michael Bloomberg and attended by top officials from the department.

Robertson says Canada is an embarrassing laggard on climate change under the Harper government and says he hopes the Oct. 19 election produces a government that plays a more constructive role.

His comments came at the end of a formal luncheon, in a panel discussion featuring three mayors -- Robertson, and peers from Japan and Nigeria.

The Vancouver mayor met Secretary of State John Kerry, who delivered opening remarks at the event, although he left before the post-luncheon panel discussion started.

In an interview later, Robertson said he keeps hearing questions about Canada's climate record -- from people in Washington and at the Vatican during a recent visit.

He is to attend an event at the White House later today.

American officials did not comment on Canadian domestic policy. They did, however, arrange media interviews with the visiting mayors. Robertson said he was invited to the, "Our Cities, Our Climate," summit several weeks ago.