Mark Esper, who served as U.S. Secretary of War during President Donald Trump’s first term, is warning that the war with Iran may continue for years while Washington risks losing focus on China. He described Beijing as America’s “greatest adversary” and said its power continues to grow.

During a panel discussion Thursday at the LSEG and Eurasia Group GZERO Summit in London, Esper said he could see the conflict continuing “well into 2027.” He also raised the possibility that the war could be handed to the next U.S. administration in three years.

Esper said both sides may eventually become willing to pursue a negotiated settlement. However, he said Trump would face the difficult task of securing a deal that restores the Strait of Hormuz to the status quo and improves upon the JCPOA negotiated under former President Barack Obama.

The political consequences of any agreement could also weigh heavily on the decision. Esper said another possible course would leave the conflict unresolved until the next administration takes office in 2029.

Speaking with CNBC on the sidelines of the summit, Esper said he did not expect the war to end “in the foreseeable future.” He predicted an extended conflict marked by a continuing American blockade and intermittent action by both sides.

“I think it continues at this type of pace where we see the American blockade continue, we see occasional outbursts from either side, and it drags along,” Esper said. His assessment offered little expectation of a quick resolution.

The war is now in its eighth month and has reached an impasse. Trump said Wednesday that making a deal with Tehran “isn’t really something that I want to do,” while reports indicated U.S. officials were considering renewed large scale military operations in the coming weeks.

Esper served as U.S. Secretary of War from July 2019 until November 2020. He said he had long supported “the economic strangulation” of Iran but warned that such a strategy requires patience from Washington.

“The challenge is that policy requires time, discipline and patience, and those aren’t things that the states are typically good at doing,” Esper said. He added that economic pressure could have an impact without necessarily forcing Iran back to negotiations.

Esper called that approach “the least worst option at this point in time.” Over the summer, Trump announced stronger sanctions and economic restrictions under a strategy he called “Economic D-Day,” and the administration has promoted the results of its economic warfare campaign.

Yet Esper’s larger warning centered on China, which he said was expanding its capabilities while American attention remained fixed on Iran. “China is our greatest adversary,” he said.

“It’s the lurking threat out there that we’re not paying attention to because we’re so focused, and have been for 20 plus years now, on the Middle East, and Europe is focused on Russia.” Esper said Beijing continued building economic, technological and diplomatic power while conducting “the largest military buildup in history.”

“We’re just not paying enough attention to the Chinese,” Esper told CNBC. “They’ve told us by 2049 they want to dominate the Indo-Pacific region and the world for all intents and purposes. They want to be able to call the shots and dictate global governance.”

Esper said China had pursued that objective for at least 30 years. He argued that Beijing used the world trading system following its entry into the WTO to strengthen both its economy and military.

He pointed to Chinese dominance in electric vehicles, rare earths, solar panels and critical materials. Esper attributed that position to the Chinese government’s ability to “consolidate control” and direct its economy, warning, “They have a game plan, and they’re and they’re executing it.”

Esper said the United States should concentrate its efforts on China alongside European and Asian allies. He called for cooperation encompassing military alliances as well as diplomatic, economic and technological action, while CNBC said it contacted both the U.S. and Chinese governments for comment.