The United States and 10 Southeast Asian nations were set to kick off joint maritime naval exercises Monday, including drills in the disputed South China Sea, as Washington ramped up its moves against alleged "bullying" in the disputed waterway by Beijing.

Eight warships, four aircraft and more than a thousand personnel from the U.S. and all 10 countries from the Association of Southeast Asian Nations were taking part in the first ASEAN-U.S. Maritime Exercise (AUMX). Lasting five days and starting at the Sattahip Naval Base in Thailand and ending in Singapore, the drills come amid soaring tensions between Washington and Beijing, especially over the South China Sea.

But those tensions were likely to be balanced out by the ASEAN nations, some of which have taken a softer approach in their dealings with Beijing. China and ASEAN held similar joint maritime exercises — the first of their kind — last October.