Secretary of State John Kerry arrived in the Philippines Tuesday for a two-day trip that could fast-track a deal on expanding the US military presence as a territorial dispute simmers with China.
Kerry flew to Manila as the two allies are in the final stages of hammering out a deal allowing more US troops, aircraft and ships to temporarily pass through the Philippines, where the last US bases closed in 1992.
He will also visit areas devastated by Super Typhoon Haiyan last month, highlighting a massive US humanitarian response to the disaster which contrasted with a modest contribution from regional power China.
"Kerry's visit can be expected to act as a catalyst for change," John Blaxland, a security and defence analyst at Australia National University's College of Asia and the Pacific, told AFP.
"He will be eager to leverage the visit to speed up and finalise arrangements and assure the Philippines and other regional powers that the US is not just a fair-weather friend," Blaxland said.
Kerry will meet with Foreign Secretary Albert del Rosario and President Benigno Aquino later Tuesday to discuss ways for "broadening of economic and security cooperation", the foreign department said.
"Humanitarian assistance and disaster response and cooperation on regional issues are also expected to be on the agenda," it said in a statement. The United States, the former colonial power in the Philippines, has been the greatest contributor of aid following the typhoon which left nearly 8,000 dead or missing, and four million people homeless.
Washington deployed an aircraft carrier group and committed 1,000 Marines and $20 million in a mobilisation that served as a preview of the deal's intensified defence engagement.
Beijing meanwhile drew scorn with an initial offer of just $100,000 to the Philippines, a Washington ally with which it is locked in a dispute over sovereignty of islands in the strategically vital South China Sea.
Del Rosario and Aquino have been rallying pro-US sentiment to blunt China's muscle-flexing in the region.
Ian Storey, a senior fellow at the Institute of Southeast Asian Studies in Singapore, said Washington's humanitarian response could help it secure the military pact with Manila.
"America's immediate, massive and generous support in the aftermath of Super Typhoon Haiyan could well hasten negotiations on US military rotational deployments through the Philippines," he said.
China's growing assertiveness in the region as well as the increasing frequency of deadly natural disasters in the Philippines "underscore the growing importance of Manila's alliance with Washington", Storey said.
Kerry, who is touring the Philippines for the first time since taking office, will travel to the typhoon-ravaged town of Tacloban on Wednesday.
Tensions between the Philippines and China have risen in recent years as Beijing becomes more forthright in asserting its claim over most of the potentially resource-rich South China Sea.
Earlier this year, Manila took Beijing to a United Nations tribunal over the contested Scarborough Shoal, which lies about 220 kilometres (135 miles) from the Philippines' main island of Luzon and has been occupied by Chinese vessels since last year.
In a bid to showcase its increasing military alliance with the United States, Manila held war games near the territory earlier this year, further stoking tensions with Beijing.
China's recent declaration of an Air Defence Identification Zone in the East China Sea -- which has infuriated Japan and South Korea -- has also raised concerns in the Philippines.
Storey said that while Beijing had not officially declared a similar air cover for the South China Sea "it might do so in the near future".
"During Kerry's visit to the Philippines, both sides will likely reiterate the importance of freedom of navigation at sea and in the air," he said.
The United States already has a long-time ally in the Philippines -- until 1992 it had a permanent military presence at two bases in the island nation.
The bases were closed amid nationalist opposition, but the current administration led by Aquino has repeatedly said it wants to build a stronger alliance with the US.