The United States and China are close to reaching an agreement on social media platform TikTok but a deal could hinge on Chinese demands for trade concessions, U.S. Treasury Secretary Scott Bessent said Monday before entering a second day of talks in Madrid.

The U.S. and China delegations are discussing the divestment from TikTok by Chinese owner Bytedance as part of broader talks on tariffs and economic policy.

"Our Chinese counterparts have come with a very aggressive ask," Bessent told reporters alongside U.S. Trade Representative Jamieson Greer.

"We will see if we can get there at present. We are not willing to sacrifice national security for a social media app," he said.

U.S. and Chinese officials, led by Vice Premier He Lifeng, concluded a first day of talks in Madrid on Sunday on their strained trade ties, a looming divestiture deadline for TikTok, amid Washington's demands that its allies place tariffs on imports from China over its purchases of Russian oil.

TikTok faces a potential ban in the U.S. unless it moves to U.S. ownership. The most likely result of the Madrid talks is seen as another extension of a deadline for TikTok owner ByteDance to divest its U.S. operations by September 17 or face a U.S. shutdown.

The latest round of U.S.-China negotiations - taking place in the baroque Palacio de Santa Cruz, home to Spain's foreign ministry - are the fourth in four months.

Bessent said both sides had made good progress on technical details but reaching a deal on other issues would be challenging.

Extending the TikTok divestment deadline would depend largely on how talks went on Monday, he said.

"From the Chinese perspective, they view as part and parcel of the potential TikTok deal a variety of matters, whether it's tariffs or other measures that have been taken over years," Greer said.

But the United States was not in a position to simply eliminate every measure it had ever taken to try resolve the issue, he added.

"We still have to grind through negotiations and discussions of the common understanding, and I don't think this is the moment to just pull all those things."

Chinese Foreign ministry spokesperson Lin Jian said China had no new information to give.

"Regarding TikTok, China has repeatedly stated its position," Lin said at a press conference in Beijing on Monday.

Delegations led by Bessent and Chinese Vice Premier He have met in European cities since May to try to resolve differences that prompted U.S. President Trump to raise tariffs on Chinese imports and sparked tit-for-tat measures, including similarly high import duties by China on U.S. goods and a halt in the flow of rare earths to the United States.

The delegations last met in Stockholm in July, where they agreed to extend for 90 days a trade truce that sharply reduced triple-digit retaliatory tariffs on both sides and restarted the rare-earth exports from China to the United States.

Experts had low expectations of a significant breakthrough in Madrid.

"I'm not expecting anything substantive between the United States and China unless and until there is a one-on-one meeting between Trump and (Chinese President) Xi," said William Reinsch, a senior trade adviser at Washington think tank the Center for Strategic and International Studies.

"Setting that up is really what these talks are all about."

Trump has repeatedly expressed interest in a meeting with Chinese President Xi Jinping, but Reinsch said the Chinese would not agree to such a meeting until they knew the outcome and were pushing for further easing of U.S. export controls on chips and other high-tech goods.

"This meeting is an opportunity to measure each other's positions and to learn more about each side's red lines," Reinsch said.

China's embassy in Madrid notified reporters of a potential concluding news conference on Monday afternoon, indicating the talks could wrap up quickly.

Bessent is due to be in London on Tuesday to meet British Finance Minister Rachel Reeves ahead of Trump’s state visit to the UK, which starts on Wednesday.

Even if a deal over Chinese divestment from TikTok was not reached it would not affect relations, Bessent added.

"It's still very good at the highest levels," "Ambassador Greer and myself have great respect for all counterparts."