SAN FRANCISCO • Prime Minister Lee Hsien Loong, who is on a week- long visit to the United States, met California Governor Jerry Brown and visited Silicon Valley on Thursday.

The Prime Minister's Office said Mr Lee and Mr Brown reaffirmed the strong economic ties between Singapore and California.

Singapore was California's 12th-largest export destination for goods in 2013, and the largest in Asean.

The two men also discussed domestic and regional developments.

Mr Lee emphasised the importance of continued US engagement of Asia and the swift ratification of the Trans-Pacific Partnership.

The trade pact, which gathers 12 countries of the Pacific Rim and includes the US and Asean members Singapore, Malaysia, Vietnam and Brunei, was signed last week.

In Silicon Valley, Mr Lee met business leaders Elon Musk, chief executive of electric car company Tesla Motors and rocket company SpaceX; Eric Schmidt, executive chairman of Google holding company Alphabet; and Sundar Pichai, CEO of Google.

Mr Lee said in a Facebook post that they talked about new technologies and global trends, and Singapore's Smart Nation ideas.

"Elon Musk gave me a brief but exhilarating ride in the Tesla Model S P90D, and I also got a spin in Google's self-driving car," he said.

Mr Lee also met Mr Ian Clark, CEO of biotechnology company Genentech, which has a biologics plant in Tuas. At Google, Mr Schmidt and Mr Pichai gave Mr Lee a print of the winning doodle from the 2015 Singapore Doodle 4 Google competition, which was by eight-year-old Moh Journ Haydn of Beacon Primary School.

He also met Singaporeans working at Google. "Many of them are engineers, and we talked about how we must make engineering more attractive as a career in Singapore."

Mr Lee will attend the special US-Asean Leaders Summit hosted by US President Barack Obama at the Sunnylands estate next week.