Turkish President Tayyip Erdogan has vowed that his country would finance a huge road project in Bosnia as the Balkan country prepares to host his speech to thousands of Turks from Western Europe and elsewhere.

In a Sunday ceremony, Erdogan watched as transport ministers of Bosnia and Turkey signed a letter of intent for the construction of the highway that would connect Belgrade and the Serbian capital of Sarajevo.

Erdogan expressed hope that the ministers would reach a final agreement in summer on technical aspects of the project which is estimated to cost 3 billion euros ($3.5 billion). He said Turkey’s Exim Bank should be involved in the financing of the large project which also faces domestic opposition in Bosnia, especially from minority Serbs.

The pledge for the huge investment could be viewed as a sign of Erdogan’s appreciation for Bosnia’s approval of his election rally. Many Western European countries have refused to allow such rallies on their soil, forcing thousands to travel to Sarajevo where Erdogan would address them later on Sunday.

Organizers of the rally expected up to 15,000 people, mostly from Germany, the Netherlands and Austria and other countries across the Balkans, to attend the event.

Erdogan criticized Western European governments for blocking rallies by him and other Turkish officials.

“If thousands of people coming from different parts of Europe cannot meet the leader they want to hear, that would not be right for me. Hence we will meet with them here,” Erdogan told a news conference,” he said.

The Turkish leader also reacted to reports that he could be the target of an assassination attempt during his visit to the Balkans.

“This news reached me and indeed that is why I am here,” said Erdogan, adding, “Such threats and operations cannot deter us from this path.”

Heavy police deployment could be seen around the Zetra Olympic hall, where Erdogan’s supporters waved Turkish and Bosnian flags.

“We came to Sarajevo just for one day to support our savior Erdogan,” said Coskun Celiloglu, a Macedonian student of Turkish descent, adding, “Turkey is our mother nation.”