United Nations General Secretary Ban Ki-moon on Saturday warned of a worsening rights situation across Central Asia, as he ended a visit to energy-rich Central Asia in ex-Soviet Turkmenistan.

Ban said he "heard concerns about the deterioration of some aspects of human rights -– a shrinking of democratic space", during his first trip to the region in five years.

Up to four thousand people from Muslim former Soviet Central Asian countries are believed to have joined Islamic State jihadists, a report published on Tuesday said.

Often driven by poverty, some "2,000 to 4,000 have in the past three years turned their back on their secular states to seek a radical alternative," the International Crisis Group said in a briefing on the region.

In the Iraqi town of Taza Khurmatu, a motley brigade of Shiite Turkmen locals adjust their weapons and headscarves before heading out to defend their homes from encroaching Sunni militants.

The men range from those in their teens, yet to grow a mustache or see combat, to elders approaching retirement and weary of war.

Turkmenistan's ruling party secured the most number of seats in legislative elections while a new party set up to diversify politics in the ultra-controlled state won its first-ever mandates, official results said Thursday.

Sunday's elections were marked by a total lack of any opposition to the dominance of President Gurbanguly Berdymukhamedov over the gas-rich Central Asian state, despite being billed as the first multi-party polls in its history.

The ex-Soviet Central Asian state of Turkmenistan on Sunday held its first multi-party legislative elections, but with no opposition to trouble the dominance of President Gurbanguly Berdymukhamedov.

Turkmens headed to polling stations in the gas-rich country after polls opened at 7:00 am local time (0200GMT) to choose 125 candidates for the seats in the Majlis, or parliament, for the next five years.

Turkmenistan's president announced Saturday he was stepping down as leader of the ruling party while he remained in office to promote a multi-party system in the isolated former Soviet state.

President Gurbanguly Berdymukhamedov told a party congress that he was resigning as leader of the ruling Democratic Party, which he has led since 2006, because he wanted to remain above party politics, according to television footage broadcast Saturday evening.

U.S. pop diva Jennifer Lopez appeared at a birthday bash for Turkmenistan's hardline leader but would have abstained if she had known of "human right issues of any kind" regarding him, a spokeswoman said Monday.

And she only wished "Happy Birthday" to Gurbanguly Berdymukhamedov as a "gracious" last-minute favor when asked to by a Chinese oil company which organized the weekend event, her publicist said in a statement.

The Central Asian state of Turkmenistan, which shares a 1,000 kilometer border with Iran, has accepted the credentials of the first ever Israeli ambassador to the country, state media said Wednesday.

President Gurbanguly Berdymukhamedov received the ambassadorial credentials of senior Israeli diplomat Shemi Tzur, the government newspaper Neutral Turkmenistan said.

Turkmenistan said Saturday that it would try to recruit international investors for a new gas pipeline project that would link Central and South Asia.

The energy-rich state plans to pitch the project to international oil and gas majors and financial institutions in the autumn, the Neitralny Turkmenistan newspaper reported.

With a production of Shakespeare's "Othello" and even an opera, cultural life in Turkmenistan is slowly coming back after grinding to a halt under the rule of eccentric despot Saparmurat Niyazov.

Niyazov, who died in 2006, notoriously ordered the closing of the Central Asian state's theatres in 2001 and now his successor Gurbanguly Berdymukhamedov is seeing to a very cautious relaxing of control.