The Philippines is already laying out plans to buy new equipment, hire more guards and review screening procedures to improve security at its main airport to levels acceptable to the United States.
The US Department of Homeland Security said in a travel advisory on Wednesday that security at Manila's Ninoy Aquino International Airport was not "consistent" with international standards.
It urged travellers to exercise "increased caution", and directed airlines to notify passengers of its assessment.
Philippine transport and security officials said they were already addressing concerns raised by the US even as they gave the assurance that lapses did not indicate a vulnerability to terrorist attacks.
"We are not vulnerable to terrorist attacks... That was not what was indicated (in the assessment). I think it was the way the airport was being managed, the way passengers are being screened, the inadequate equipment they saw," Defence Secretary Delfin Lorenzana told reporters yesterday.
Presidential spokesman Salvador Panelo said in a text message that new X-ray machines, walk-through metal detectors and alarm systems would be installed at the airport by the second quarter of next year.
"Ensuring the safety of the travelling public is one of the critical interests of our government in view of the looming threat of terrorism. We assure everyone that the Philippine government... is prioritising the implementation of strict security measures at (the airport)," he said.
More airport guards are being hired, Transportation Secretary Arthur Tugade said on Thursday.
The airport currently has 1,345 guards manning three terminals and runways that span some 440ha.
The Manila International Airport Authority, which runs the airport, is hiring another 176. The airport authority is also installing three times as many surveillance cameras. There are now about 700 cameras.
Security agencies, meanwhile, are running new background checks on newly hired airport staff, and training is being scheduled to instil a "security culture" among long-time employees.
US Ambassador to the Philippines Sung Kim said in a statement on Thursday that the State Department had earmarked US$5 million (S$6.8 million) to help the Philippine government procure new technology, streamline screening operations, and modernise the security infrastructure at its airport.
All these measures are in line with recommendations contained in a report submitted by the Transportation Security Administration that the Homeland Security Department cited in its travel advisory.
"Let's just follow. Let's comply. If they still flag us after we have complied, then maybe that would be the time that we would refute," airport authority general manager Ed Monreal told reporters on Thursday.
Manila's Ninoy Aquino International Airport, the primary gateway to the Philippines, topped the list of the world's worst airports on the travel website The Guide To Sleeping In Airports from 2011 to 2013 due to leaking toilets, broken air-conditioning units, long queues, dishonest taxi pricing, flight delays, and extortion.
Stung by the humiliation, the government allocated some 1.3 billion pesos (S$33.8 million) on major renovations.
It refurbished toilets, provided Wi-Fi access, installed automated immigration lanes, expanded waiting areas and opened more transport options for travellers.
It also cracked down on dishonest staff, built new taxiways and introduced stricter rules on pilots to reduce flight delays.
The efforts paid off. The airport was taken off the world's 20 worst airports list last year. It also was not among Asia's five worst airports.