Trump congratulates Erdogan despite Turkish referendum controversy

Criticism of Turkey's referendum result grew louder on Tuesday, with the European observers claiming close to three million votes could have been manipulated.

Nevertheless, US President Donald Trump telephoned to congratulate counterpart Recep Tayyip Erdogan after his 51.4% victory on Sunday.

The win gives Erdogan the power to make significant constitutional changes, granting him sweeping powers in Turkey's transformation from a parliamentary democracy to a presidential republic.

While the result confirmed a much lower margin than had been expected, an observer from the Council of Europe said on Tuesday that up to 2.5m votes could have been manipulated, far eclipsing Erdogan's victory margin of 1.3m votes.

Furthermore, the pro-Kurdish opposition Peoples' Democratic Party complained that 3m votes had been unstamped.

Trump and Erdogan spoke via phone on Monday in a pre-arranged call, in which the US President offered congratulatory words, as well as discussing topics such as the ongoing conflict in Syria.

Other world leaders have struck a different tone to Trump after the vote in Turkey, in response to preliminary findings from international bodies which described the referendum as taking place "on an unlevel playing field."

Trump and Erdogan spoke via phone on Monday in a pre-arranged call

German chancellor Angela Merkel urged Erdogan to open dialogue with some of his major opponents within the country in order to move the country forward.

"The German federal government expects the Turkish government to seek respectful dialogue with all political and societal powers in the nation after a tough referendum campaign," the statement from Merkel and German foreign minister Sigmar Gabriel read.

Turkey was plunged into political upheaval last summer when a coup attempt in July failed and 265 people were killed as a result.

Erdogan launched a major crackdown on his opponents in the aftermath of the coup, with thousands of judges and high-ranking security officials dismissed and dozens of politicians and journalists arrested.

The Turkish Lira pushed 2.5% higher on Monday before being reined in towards the end of the day, with London Capital Group analyst Ipek Ozkardeskaya asserting that the USDTRY rate would break a critical resistance if it heads over 3.80.

"A break above 3.80 should suggest renewed anxiety against the lira and could encourage a fresh attempt toward the 4.00 level," Ozkardeskaya said.