About 700 Turkish demonstrators gathered in a border town in the southern province of Hatay on Sunday.
The Turkish Freedom and Solidarity Party had organized the gathering.
The demonstrators also expressed solidarity with the Syrian nation.
The Hatay protest comes as Syrians began voting in a referendum on a newly drafted constitution on Sunday.
The draft constitution excludes Article 8, which declared the ruling Baath Party as the “leader of the state and society.” It also creates a multiparty system in Syria and puts a limit of two seven-year presidential terms.
The referendum in Syria was held two days after Tunisia hosted a meeting of the so-called “Friends of Syria” group, proposed by France and the United States, on February 24. Russia, Lebanon and several other countries boycotted the meeting.
Syria has been experiencing unrest since mid-March 2011, with demonstrations being held both against and in favor of President Bashar al-Assad.
Assad said on February 20 that “some foreign countries” are fueling the turmoil in Syria by supporting and funding “armed terrorist groups fighting against the government.”