President Asif Ali Zardari will undertake a two-day visit to Tajikistan from July 28 to 29, sources said on Saturday. On the invitation of Tajik President Enomali Rahman, the President of Pakistan will undertake a visit to Tajikistan. A trilateral summit of Tajikistan, Pakistan and Afghanistan and a quadrilateral summit of Pakistan, Afghanistan, Tajikistan and Russia are also likely to be held during the visit.