The Turkish president has brought together more than 20,000 people in the Bosnian capital to back his election bid. But some leaders are worried his growing influence in the Balkans could lead to regional instability.
"Are you ready to support me with a record number of votes in the presidential election?" Erdogan asked the crowd. At moments, the crowd chanted "Sultan Erdogan."
"I have one request from you: take an active role in the political parties in the countries you live in. You should take a place in those parliaments."
The elections mark Turkey's official transition to an executive-style presidential system that some say will give the presidency too much power.
'Interfering'
Some leaders in Bosnia-Herzegovina have expressed concerns about Erdogan's growing influence in the country, with Bosnian Serb leader Milord Dodik saying the Turkish leader was "interfering a lot" in the country's affairs.
But Bosnian Muslim leader Bakir Izetbegovic dismissed the allegations of interference as spite, saying there were "many frustrated Bosniak (Muslims) who do not like him in this country."
Ahead of the rally, Erdogan met with Izetbegovic. During a joint press conference, the Turkish president acknowledged criticism of his visit, saying Ankara is only interested in helping the Balkan country develop.
"Our country has no secret agenda other than the welfare, unity and economic development of Bosnia-Herzegovina. Efforts to prove otherwise are futile."
But the Washington-based Center for European Policy Analysis (CEPA) has pointed to Turkey's growing influence in Bosnia-Herzegovina and the Balkans as a possible source of instability.
"Initially seen as a useful supplement to the EU and the US, especially among the region's Muslim populations, Turkey's political interjections and self-declared 'neo-Ottomanism' are increasingly viewed with suspicion."
Why are German and Turkish relations so strained?
German-Turkish relations have deteriorated since the failed coup against Turkish President Erdogan in 2016 and the crackdown that followed. DW looks at some of the key moments that soured ties between Berlin and Ankara.
Image: picture-alliance/POP-EYE/B. Kriemann
The Böhmermann affair
March 31, 2016: Turkish President Recep Tayyip Erdogan filed charges against German comedian and satirist Jan Böhmermann over his "defamatory poem" about the Turkish leader. German prosecutors eventually dropped the charges on October 4, 2016, but the case sparked a diplomatic row between Berlin and Ankara.
German lawmakers pass resolution to recognize 1915 Armenian Genocide
June 2, 2016: The resolution passed almost unanimously. In response, Turkey recalled its ambassador in Berlin and Germany's Turkish community held protests in several German cities. Turkey had repeatedly criticized the use of the term genocide to describe the Ottoman-era Armenian killings, arguing that the number of deaths had been inflated, and that Turkish Muslims also perished in the violence.
Image: Getty Images/AFP/S. Gallup
Tensions following failed coup in Turkey
July 15, 2016: A faction of the Turkish military tried to overthrow President Recep Tayyip Erdogan, but ultimately failed. Ankara accused Berlin of not taking a clear stand against the coup attempt or not doing anything about exiled preacher Fethullah Gulen's organization, who Erdogan blames for orchestrating the failed coup.
Image: picture-alliance/dpa/S. Suna
Germany criticizes post-coup purge
Immediately following the attempted coup, Turkish authorities purged the army and judiciary, detaining thousands of people. The purge expanded to include civil servants, university officials and teachers. German politicians criticize the detentions. Turkish diplomats, academics and military members fled the country and applied for asylum in Germany.
Image: picture-alliance/dpa/S. Suna
Kurdish rallies in Cologne
Erdogan's post-coup crackdown has also been condemned by Kurdish protesters at several mass demonstrations in the west German city of Cologne. Often the rallies have called for the release of Abdullah Ocalan, the jailed leader of the Kurdistan Workers' Party (PKK), which Turkey considers to be a terror group. Ankara has accused Berlin of not doing enough to stop PKK activities.
Image: picture-alliance/AP Photo/M. Meissner
Arrest of German citizens in Turkey
February 14, 2017: Deniz Yücel, a correspondent for the "Welt" newspaper, was taken into custody in Turkey. Other German nationals, including journalist Mesale Tolu and human rights activist Peter Steudtner were detained in Turkey for what Berlin dubbed "political reasons." Turkey accused them of supporting terrorist organizations. All three have since been released pending trial.
March 2017: A number of German localities blocked Turkish ministers from holding rallies in their districts ahead of an April referendum in Turkey to enhance President Erdogan's powers. The Turkish leader then accused Germany of using "Nazi tactics" against Turkish citizens in Germany and visiting Turkish lawmakers. German leaders were not amused by the jibe, saying Erdogan had gone too far.
Image: picture-alliance/dpa/O. Berg
Spying allegations
March 30, 2017: Germany accused Turkey of spying on hundreds of suspected Gulen supporters as well as over 200 associations and schools linked to the Gulen movement in Germany. Turkish asylum-seekers have since accused officials working in Germany's immigration authority (BAMF) of passing on their information to media outlets with ties to the Turkish government.
Image: Imago/Chromeorange/M. Schroeder
Erdogan urges German-Turks not to vote for 'enemies of Turkey'
August 18, 2017: Turkish President Recep Tayyip Erdogan slammed three of Germany's main political parties as "enemies of Turkey" and told Turks living in Germany not to vote for them in September's general election. He singled out Merkel's Christian Democrats (CDU), the Social Democrats (SPD), and the Greens. Merkel said Erdogan was "meddling" in Germany's election.
Image: picture-alliance/abaca/AA/M. Ali Ozcan
Merkel says Turkey should not become EU member
September 4, 2017: German Chancellor Angela Merkel said during an election debate that she didn't think Turkey should become a member of the European Union and said she would speak with other EU leaders about ending Ankara's accession talks. In October, she backed a move to cut Turkey's pre-accession EU funds.
Image: Reuters/F. Bensch
Turkey's military offensive in Afrin
January 20, 2018: The Turkish military and their Syrian rebel allies launched "Operation Olive Branch" against the Kurdish-held enclave of Afrin in northern Syria. The move was criticized by German politicians and prompted large protests by Kurdish communities in Germany.
Image: Getty Images/AFP/O. Kose
Journalist Deniz Yücel released from prison
February 16, 2018: Turkey ordered the release of German-Turkish journalist Deniz Yücel after he'd been held for over a year without charge. According to Turkish state media, Yücel was released on bail from pre-trial detention. Prosecutors asked for an 18-year jail sentence for Yücel on charges of "terror propaganda" and incitement.
Image: picture-alliance/Eventpress/Stauffenberg
Özil quits
July 2018: German footballer Mesut Özil quit the national team following the fallout from his meeting with the Turkish president. Özil said he was being made a scapegoat for Germany's forgettable performance at the FIFA World Cup in Moscow because of his Turkish heritage. Erdogan praised Özil's decision and slammed the "racist" mistreatment of the footballer.
Image: picture-alliance/dpa/Presidential Press Service
Travel ban lifted
August 2018: A Turkish court removed the travel ban on German journalist Mesale Tolu, who was arrested last year on terrorism-related charges. But the trial against Tolu, who has since returned to Germany, is set to continue. Her husband, Suat Corlu, who is facing similar charges, has been ordered to remain in Turkey.