Head of IKN Authority Bambang Susantono traveled to Kazakhstan early this week to sign the MoU with Astana Mayor Zhenis Kassymbek at a ceremony on Monday, during which the two officials also declared Nusantara and Astana as sister cities.

Indonesian Ambassador to Kazakhstan Fadjroel Rachman said the agreement was a high-water mark in the two countries’ diplomatic relationship, which marked its 30th anniversary this year.

"Thank you to everyone who has worked tirelessly, including Astana Mayor Zhenis Kassymbek, [...] who has been effective in realizing the Nusantara-Astana sister city collaboration plan," Fadjroel said in a statement.

Astana became the capital of Kazakhstan in 1997, when then-president Nursultan Nazarbayev decided to relocate the country’s administrate center from Almaty, now a business and cultural hub.

The move was widely questioned at the time because of Astana’s relative isolation in the northern steppes and its notoriously frigid winters, during which temperatures could plunge as low as minus 51 degrees Celsius.

During his trip to the Kazakhstani capital, Bambang also met with a number of senior officials and was briefed on Astana’s sustainable development, including from chief architect Amanzhol Chikanayev, the Indonesian Embassy said in a statement.

At a separate event held in Astana on Wednesday titled “Investing in Indonesia’s Future Capital: Smart and Sustainable Forest City Nusantara”, Bambang made a sales pitch to local investors on opportunities in Nusantara, which he billed as a green and sustainable urban complex.

Also on Wednesday, the Transportation Ministry unveiled a plan to build an extensive railway network that would connect Nusantara with major cities around the planned capital city.

The ministry's Railways Director General Risal Wasal told a House of Representatives hearing that day that the government would prioritize the development of three railway lines in 2024.

Risal said the ministry was currently conducting an environmental impact analysis for three railway lines that would connect Nusantara with East Kalimantan's capital Balikpapan, with the Sepinggan Airport and one commuter line that would link downtown Balikpapan with the planned new capital's administrative center.

"We're also conducting an investigative survey for the opening of a trans-Kalimantan railway network and another network within East Kalimantan," Risal told Commission V lawmakers overseeing transportation and infrastructure.

The ministry expects that some of the railway network could be operational after the year 2025.

In recent months, the administration of President Joko "Jokowi" Widodo has unveiled designs for major infrastructure projects in Nusantara in an attempt to woo private investors to invest in the planned new capital.

In early June, President Jokowi ordered the construction of a VVIP airport at the site of Nusantara.

In a presidential regulation (Perpres) issued last month, the President has given authority to the Public Works and Housing Ministry to carry out the project, and has ordered the Transportation Ministry to be in charge of the airport's operations.

"This VVIP airport is a special airport dedicated to government business in the IKN [Nusantara capital city]," the presidential regulation stipulates.