Boston City Councilor John Tobin is calling on the new owner of the John Hancock Tower to reopen the skytop public observation deck, which has been closed since the terrorist attacks of Sept. 11, 2001.

Tobin yesterday made the request of Normandy Real Estate Partners, which along with its investment partner assumed ownership of Boston's tallest building at an auction earlier this week.

The city councilor argued that security concerns no longer justify keeping the space on the tower's 60th floor closed, especially since similar public spaces have been reopened at the Empire State Building in New York and at other skyscrapers nationwide.

"Why is this the only observation deck in North America that did not reopen after 9/11?" he said.