Taipei, Taiwan - Five US lawmakers arrived in Taipei for a surprise visit on Sunday amid escalated tensions across the Taiwan Strait, following a trip earlier this month by Nancy Pelosi, the speaker of the US House of Representatives.

According to the American Institute in Taiwan (AIT), which acts as the de facto US embassy, the two-day visit is part of a larger trip to the Indo-Pacific region.

Discussions are to focus on regional security, trade, and investment, among other issues.

Taiwan's foreign ministry welcomed the visit, saying that the delegation will meet with President Tsai Ing-wen and Foreign Minister Joseph Wu.

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The visiting lawmakers, from both Republican and Democratic parties, are Senator Ed Markey and Representatives John Garamendi, Alan Lowenthal, Don Beyer, and Aumua Amata Coleman Radewagen.

China increased pressure on Taiwan both militarily and economically after a 19-hour visit to Taipei by Pelosi on August 2-3.

Legislator Lo Chih-cheng of the ruling Democratic Progressive Party (DPP) said the US group's visit at such a sensitive time, coming shortly after China's large-scale drills near Taiwan, shows that Beijing cannot prevent leading political figures from around the world from visiting Taiwan.

"Their arrival also delivers an important message that American people are standing with Taiwanese people," Lo said.

Tsai's office has not released any details about the meeting. In Beijing, China's Defense Ministry spokesperson Wu Qian said on Monday that the visit by the US delegation undermined China's sovereignty and territorial integrity.

Taiwan has had an independent government since 1949, but China considers the island part of its territory. In 1979, Washington formally cut diplomatic ties with Taipei and built relations with Beijing.