Turkish police fired tear gas to stop a small group of anti-war protesters approaching parliament on Thursday as deputies debated a motion that could authorise military action in Syria if the government deems it necessary.
A Reuters reporter saw 25-30 protesters chanting "We don't want war!" and "The Syrian people are our brothers!" in front of the parliament building in the capital Ankara.
Turkish artillery hit targets near Syria's Tel Abyad border town for a second day on Thursday in response to a mortar fired from Syria that killed five civilians in the Turkish town of Akcakale on Wednesday.
Parliamentarians were debating in a closed session whether to extend a five-year-old authorisation for foreign military operations, an agreement originally intended to allow strikes on Kurdish militant bases in northern Iraq.
The memorandum sent to parliament by the government overnight said the Syrian military had launched aggressive action against Turkish territory in recent weeks, presenting "additional risks" to Turkey's security.