US Vice President Joe Biden is expected Wednesday to urge India to further open its doors to foreign investment, during his visit to boost bilateral ties between the world\'s two largest democracies. Biden, the first US vice president to visit India in three decades, will give a speech at the Bombay Stock Exchange, set to focus on tackling barriers to strengthen two-way trade, which has hit nearly $100 billion annually. Biden arrived in Mumbai late Tuesday after holding talks with Indian Prime Minister Manmohan Singh, and other political leaders, in the capital on economic issues and the security situation in Afghanistan. Biden is the most senior US official to visit India since President Barack Obama in 2010, and the four-day visit is designed to revive momentum in flagging diplomatic ties and fire up bilateral trade. Biden will make a keynote speech at the exchange to the business community, followed by a roundtable meeting with corporate leaders at the Taj Mahal Palace Hotel. Officials have pointed to the visit as a chance to heat up the investment climate between the US and India, where the government has been trying to introduce pro-business reforms in a bid to boost the sluggish economy. Ahead of Biden\'s visit, a US official briefing journalists said there was no reason why bilateral trade \"can\'t be five times (more). Over the last 13 years, it has quintupled, and it should quintuple again.\" Both Indian Finance Minister P. Chidambaram and Commerce Minister Anand Sharma were in Washington earlier this month to pitch for greater investment and discuss India\'s readiness to open talks on a bilateral investment treaty. But a major concern in America was voiced in an open letter to Biden from a Washington-based lobby, urging him to address what it called \"India\'s unfair trade and intellectual property practices\". A major point of contention is India\'s championing of generic drugs -- which advocates say save lives in poor nations -- despite protests from Western drug firms that accuse the Indian industry of riding roughshod over patents. India in turn has been alarmed by proposals in the US Congress to curb visas for high-tech workers, which are feared to hit those employed by the flagship Indian outsourcing industry and working for American firms in the US. Biden will leave for Singapore on Thursday.