Opponents of Turkey's controversial referendum to expand the powers of President Recep Tayyip Erdogan vowed to challenge the result Sunday, after he claimed victory for the "yes" vote by the slimmest of margins.

As "no" supporters vented their anger, thousands of jubilant supporters of the ruling AKP party filled the streets of the capital, Ankara, beating drums and singing victory songs in Erdogan's name.

With nearly all of the 47.5 millions votes counted, state media reported that 51.4% had voted in favor versus 48.6% against, revealing deep divisions within the country over its future rule.

Voters were asked to endorse an 18-article reform package put forward by the ruling Justice and Development Party that would replace the current system of parliamentary democracy with a powerful executive presidency.

Alongside claims of voting irregularities, the "No" campaign said they faced intimidation and threats of violence, and independent monitors say that state media slanted coverage in favor of the president.

(Source: CNN)