The U.S. State Department's no. 2 diplomat has compared China's moves to claim new territory through island-building in the South China Sea to Russia's moves in eastern Ukraine.
Deputy Secretary of State Antony Blinken said on June 26 that China's large-scale reclamation projects are "a threat to peace and stability."
"In both eastern Ukraine and the South China Sea, we're witnessing efforts to unilaterally and coercively change the status quo -- transgressions that the United States and our allies stand united against," he said in a speech at the Center for a New American Security in Washington.
His remarks came as the Phillippines complained that China is constructing artificial islands on at least two reefs it also claims.
Blinker said the United States wants to preserve peace and freedom of navigation in the region.
"The way forward is for China, and all claimants, to freeze their reclamation activities and resolve their difference in accordance with the rule of law," he said.
China claims nearly all of the South China Sea and says it has every right to build upon reefs there.
Based on reporting by Reuters and AP
