Protests and Parties: Turkish President Claims Referendum Victory

President Recep Tayyip Erdogan's win on Sunday will greatly expand the powers of his office as he tells opponents, "it's too late now."

A woman supporting Turkish President Recep Tayyip Erdogan waves a Turkish national flag as she celebrates during a rally near the headquarters of the conservative Justice and Development Party (AKP) on April 16, 2017, in Istanbul.

Erdogan hailed Turkey for making a "historic decision" as he claimed victory in the national referendum on a new constitution expanding his powers. The "Yes" campaign to give the president expanded powers won in a tightly-contested referendum although the "No" camp had closed the gap, according to initial results. But Turkey's two main opposition parties said they would challenge the results.

Ozan Kose / AFP - Getty Images
Supporters of Turkey's president wave flags and brandish smoke bombs during a rally after the initial results of a nationwide referendum. Ozan Kose / AFP - Getty Images

A man holds a child as they wait for President Erdogan to appear for a speech at the AKP headquarters in Istanbul, on April 16.

Bulent Kilic / AFP - Getty Images
Supporters of the president celebrate the victory of the ''Yes'' campaign near Taksim Square, in Istanbul. The constitutional referendum will give President Erdogan more power by introducing a presidential system. Can Erok / Abaca
Opponents of the referendum chant slogans as they protest in Istanbul into the early Monday morning hours, April 17. Hundreds of demonstrators marched in a central neighborhood, clanking pots and pans and chanting "this is just the beginning, the struggle will continue." Cansu Alkaya / AP
Protesters take to the streets in Istanbul as the first results of the referendum emerge, April 16. Yasin Akgul / AFP - Getty Images
People celebrate late into the night in Istanbul, April 16. Ozan Kose / AFP - Getty Images
A woman flashes a four finger sign called "the rabia sign" as she celebrates and waits to greet the Turkish president when he arrives for his speech in Istanbul, April 16. Bulent Kilic / AFP - Getty Images
Erdogan's supporters celebrate in Istanbul. Can Erok / Abaca
Protesters take to the streets in Istanbul. Cansu Alkaya / AP
Riot police officers detain a protester outside the Supreme Electoral Board in Ankara, late Sunday night, April 16. Burhan Ozbilici / AP
A man reads Posta newspaper bearing a headline which translates as "Yes to New System" in Istanbul on April 17. Yasin Akgul / AFP - Getty Images
The president is greeted by his supporters as he leaves Esenboga Airport in a bus in Ankara, April 17. Yasin Bulbul / Reuters

President Erdogan greets people, accompanied by Turkish parliamentary speaker Ismail Kahraman after praying at Eyup Sultan mosque in Istanbul, April 17.

Sedat Suna / EPA
Supporters of the president await his arrival to Ankara on April 17. Elif Sogut / Getty Images
The president's supporters wave national flags as they await his arrival at the Presidential Palace on April 17. Elif Sogut / Getty Images
Supporters celebrate while waiting for President Erdogan to arrive at the presidential palace. Elif Sogut / Getty Images