The leader of Turkey’s main opposition party said Sunday that the Netherlands should apologize to Turkey for its recent mistreatment of Turkish government ministers.

"If a minister of Turkey was refused, the Netherlands should apologize to us," Republican People’s Party (CHP) leader Kemal Kilicdaroglu told a rally in Istanbul. “It’s that simple.”

He also said the Turkish people need to "come together" on Turkey's foreign policy interests, saying, "There is no right, left, or middle. This country is our country."

Last week, Turkish Foreign Minister Mevlut Cavusoglu was refused permission to land in the Netherlands, and Family and Social Affairs Minister Fatma Betul Sayan Kaya was deported from the country after being blocked from entering Turkey’s Consulate in Rotterdam.

When Turkish citizens in Rotterdam tried to peacefully protest, they were met by police using batons, dogs and water cannons, in what some analysts called a disproportionate use of force.

The incidents drew strong criticism from Ankara, including diplomatic notes sent to the Netherlands in protest.

On the April 16 referendum on constitutional changes, Kilicdaroglu said the proposed changes "concern all of us," adding that these changes would affect every citizen.

He urged voters to consider that the referendum will not change the government, but rather will change the Constitution, something "not as easily amended as other laws."

"This has nothing to do with the parties," he said, adding that "governments change, [but] the Constitution will remain."

Next month Turkish voters will be asked to approve or veto an 18-article bill which would change Turkey’s current parliamentary system to a presidential one, abolish the post of prime minister, and allow the president to retain ties to a political party.

Other changes would see the minimum age for parliamentary candidates lowered to 18 and the number of deputies rise to 600. Under the new constitution, simultaneous parliamentary and presidential elections for a five-year term would be held in November 2019.

The Yes campaign is backed by the ruling Justice and Development (AK) Party and the Nationalist Movement Party (MHP), while the main opposition Republican People's Party (CHP) and the Peoples' Democratic Party (HDP) oppose it.