China’s government warned on Tuesday it would take “forceful measures” if US House of Representatives Speaker Nancy Pelosi visited Taiwan, after the Financial Times said she would go to the Chinese-claimed island next month.

Pelosi and her delegation will also visit Indonesia, Japan, Malaysia and Singapore, and spend time in Hawaii at the headquarters of US Indo-Pacific command, the paper added, citing people familiar with the matter.

Her office and the US State Department did not immediately respond to a Reuters request for comment. Taiwan’s Foreign Ministry said it has “not received relevant information” about any visit.

The Democratic leader’s visit to Taiwan had been postponed from April, after she tested positive for Covid-19. At the time, China said such a visit would severely affect Chinese-US relations.

Speaking in Beijing, Chinese Foreign Ministry spokesman Zhao Lijian said any visit by Pelosi would “seriously undermine China’s sovereignty and territorial integrity”.

“If the US side obstinately clings to this course, China will definitely take resolute and forceful measures to firmly defend its national sovereignty and territorial integrity,” he said.

“The United States must be fully responsible for all the consequences caused by this.”

Taiwan faces mounting pressure from China, which considers the democratically ruled island its own territory. The issue is a constant irritant in ties between Beijing and Washington.

Taiwan, however, has been heartened by continued support offered by the Biden administration, which has repeatedly talked of its “rock-solid” commitment to the island.

Pelosi, a long-time critic of China, held an online meeting with Taiwan Vice President William Lai in January as he wrapped up a visit to the United States and Honduras.

The White House had expressed concern about the trip, the Financial Times said, citing three people familiar with the situation.

There were divisions in the US administration over whether Pelosi should visit Taiwan, the paper quoted two sources as saying.

Some officials believed it had been easier to justify a visit in April, as that was just after the start of Russia’s invasion of Ukraine, it added.

China sent fighters across the Taiwan Strait’s median line this month in what the latter described as a provocation. The incident came during a visit to Taipei by US Senator Rick Scott, a senior Republican and member of the Senate’s Armed Services Committee.

News of Pelosi’s August visit comes after China asked the United States on Monday to immediately cancel a potential sale of military technical assistance to Taiwan worth an estimated $108 million.