Li met the leaders of the 10-member Association of Southeast Asian Nations (ASEAN) at their gathering in Laos after a day of discussions dominated by the Myanmar civil war.
Recent months have seen a spate of violent clashes between Chinese and Philippine vessels in waters around disputed reefs and islands in the South China Sea.
Marcos raised the issue in the meeting with Li, arguing that "you cannot separate economic cooperation from political security," a Southeast Asian diplomat who attended the meeting told reporters.
The Li summit was largely focused on trade, and came the same day the premier met with Australian Prime Minister Anthony Albanese who said Beijing has agreed to lift sanctions on the lucrative lobster industry.
But Marcos told the meeting that ASEAN and China cannot pretend that all is well on the economic front when there are tensions on the political front, the Southeast Asian diplomat said.
Marcos also said that both sides should hasten talks on a code of conduct in the sea.
On Wednesday, ASEAN leaders repeated longstanding calls for restraint and respect for international law in the South China Sea, according to a draft summit chairman's statement seen by AFP.
The growing frequency and intensity of clashes in the disputed waterway are fuelling fears that the situation could escalate.
"The South China Sea is a live and immediate issue, with real risks of an accident spiralling into conflict," Singapore's Prime Minister Lawrence Wong told his fellow leaders in Wednesday's summit.
Beijing claims almost the entirety of the South China Sea, a waterway of immense strategic importance through which trillions of dollars in trade transits every year.
But several ASEAN members -- the Philippines, Malaysia, Vietnam, Indonesia and Brunei -- also have competing claims to various small islands and reefs.
- Clashes at sea -
The meeting with Li comes after a slew of violent clashes, particularly with the Philippines around the Spratly Islands.
Chinese coast guard and other vessels have rammed, water-cannoned and blocked Philippine government vessels.
And earlier this month, Vietnam issued an angry condemnation after some of its fishermen were attacked and robbed off the Paracel Islands by what it called "Chinese law enforcement forces".
Beijing responded that the islands are its sovereign territory and its personnel were taking action to stop "illegal fishing" by the Vietnamese.
US Secretary of State Antony Blinken arrived Thursday and is expected to raise the South China Sea when he holds talks with ASEAN leaders on Friday.
Daniel Kritenbrink, the top US diplomat for East Asia, accused China of taking "escalatory and irresponsible steps designed to coerce and pressure many in the South China Sea".
China has for years sought to expand its presence in contested areas of the South China Sea, brushing aside an international ruling that its claim to most of the waterway has no legal basis.
It has built artificial islands armed with missile systems and runways for fighter jets, and deployed vessels that the Philippines says harass its ships and block its fishers.
ASEAN leaders also met Japan's new Prime Minister Shigeru Ishiba and President Yoon Suk Yeol of South Korea on Thursday, and will hold a three-way summit with them and Li.
Related Links
Naval Warfare in the 21st Century
| Subscribe Free To Our Daily Newsletters |
| Subscribe Free To Our Daily Newsletters |
