Bangladeshi Prime Minister Khaleda Zia headed to Vietnam Tuesday for a three-day visit to boost trade and investment ties, her office said in a statement. Zia is scheduled to meet with Vietnam Prime Minister Phan Van Khai on Wednesday, the statement said. A 34-member delegation including some high profile business leaders accompanied the prime minister, it said, adding that during Zia's visit, the two nations are expected to sign an investment agreement to enhance their bilateral business relationship.