The transport ministry spokesman says there were no flight disturbances due to the ash clouds.
Duterte says he would "open alliances" with China, as well as Russia and seek help in the country's drug problem.
No group has claimed responsibility of the three attacks yet.
Officials say the incidents took place while President Duterte made calls to allow Filipinos fish near Scarborough shoal.
Authorities say more than 3,700 tourists had already been evacuated from tourist spots.
Singapore's ambassador, in a letter to the editor-in-chief of China's Global Times, expressed the state's disappointment with the report.
President Xi Jinping launched a sweeping crackdown on deep-rooted corruption after assuming power almost four years ago
PM Lee is scheduled to meet his Japanese counterpart Shinzo Abe and will receive the top honour for a foreign dignitary
Authorities say there were no immediate reports of any damage or injury.
He is the third priest who was slain in Mexico in the past one week.
In an eight-minute conversation, the sailor says they were being held in a jungle and beaten up.
The telescope will study the distribution of neutral hydrogen and seek to unlock answers on the evolution of the universe.
Yasay says Duterte won "an unprecedented and resounding electoral mandate" and had to deliver a change.
Authorities say that even after the collapse the main structure of the bridge was still intact.
SGSecure app will provide information and guidance to the public in case of a major crisis like a terrorist attack or fire accidents.