President Barack Obama and Chinese President Xi Jinping participate in a joint news conference in the Rose Garden of the White House Friday. Economic espionage was a focus of their conversation.

WASHINGTON — Skeptical of Chinese assurances on cyberspying, President Barack Obama on Friday laid out a fresh threat of sanctions for economic espionage emanating from China, even as he and President Xi Jinping pledged their countries would not conduct or support such hacking.

“The question now is: Are words followed by action?” Obama said, standing alongside Xi at a White House news conference.

Obama’s wariness underscored deep U.S. concerns about what officials say is China’s massive cyber campaign to steal trade secrets and intellectual property from American companies. While China has publicly denied being behind such activities, U.S. officials say their counterparts in Beijing have begun to take the matter more seriously, as well as the potential impact on ties with Washington.

“Confrontation and friction are not the right choice for both sides,” Xi said, speaking through an interpreter.

The spying tensions cast a shadow over Xi’s state visit to Washington, a grand affair complete with a formal welcome ceremony and a black-tie dinner. Obama faced criticism from some Republicans for honoring China with a state visit given the cyber concerns, as well as U.S. worries about Beijing’s human rights abuses and assertive posture in territorial disputes in the East and South China Seas.

While the latter issues were discussed during Obama and Xi’s lengthy talks, no discernable progress was made.

Xi said the Chinese have “the right to uphold our own sovereignty” in the South China Sea, where Beijing has alarmed its neighbors with a major campaign of artificial island-building. China has reclaimed about 3,000 acres of land in the past year-and-a-half by dredging sand from the ocean bed.