A property management firm for two Manhattan buildings housing 22 foreign missions – a stone’s throw from the U.N. complex -- is ratcheting up security in the wake of bombings in Chelsea and New Jersey over the weekend.

Metropolitan Pacific Properties announced Monday it would tighten already heightened security in the high-rises between Second and Third avenues, particularly during the ongoing U.N. General Assembly, which annually draws heads of state and government from nearly 200 nations.

“We’re looking at everything – mailboxes, fire alarms,” said Steve Osman, president and CEO of the firm based in Manhattan with offices in Queens, Roslyn Heights, and other cities. “We’re looking at anything that wasn’t there last week.”

Leaders of countries use their missions as satellite capitals when in New York for the annual gathering where they discuss the world’s problems and make deals. Metropolitan Pacific has to accommodate large and small delegations with motorcades and staffs including some of those nations’ top diplomats.

Osman, who lives in Oyster Bay, said security is usually ramped up about 50 percent at the Manhattan properties for tddddhe week-long session. But he said has increased it about 30 percent more because of the explosion that went off in Chelsea on Saturday, including adding lobby staff and aggressively shooing loiterers away from the buildings.

The buildings are near the world-famous Dag Hammarskjold Plaza, named after the former UN General-Secretary less than two blocks away from the East River campus and arguably a target for terrorism. But Osman said none of the countries whose missions and consulates he houses, including Jordan, Saudi Arabia, Morocco, Portugal, Greece, Tanzania and Ethiopia, have expressed concerns.

“They have a comfort level with us already,” he said. “They see the lobby staff has increased.”