Turkmenistan's President Gurbanguly Berdymukhammedov is continuing a two-day visit to Tajikistan's capital, Dushanbe.
Berdymukhammedov is meeting with Tajik counterpart Emomali Rahmon and with other government officials during his stay.
Tajikistan's Foreign Ministry says the leaders are talking about possible investment by Turkmenistan in Tajikistan's energy and transportation sectors, as well as other strategic sectors of Tajikistan's economy.
Joint efforts on a project to build a new railway that would link the two countries by passing through Afghanistan also was on their agenda.
They also were expected to discuss regional security after the withdrawal of NATO-led forces from Afghanistan at the end of 2014.
Berdymukhammedov's visit is his first to Tajikistan since 2010.
Rahmon traveled to Turkmenistan's capital, Ashgabat, twice in 2013 for talks with Berdymukhammedov.