Turkey's parliament has approved the deployment of its troops in Lebanon to join to the UN peacekeeping mission.
Many Turks oppose sending troops to Lebanon
Lawmakers, recalled from the summer recess for the emergency session, voted 340-192 in favour of sending the troops, despite widespread opposition.
Thousands protested in the capital Ankara, calling on politicians not to send troops to fight fellow Muslims.
Several were detained. UN chief Kofi Annan arrived in Ankara as the parliament began its debate.
This is Mr Annan's last stop in a regional tour to raise support.
From Egypt, he suggested Israel might shortly lift its air and sea blockade of Lebanon.
"I don't want to raise any false hopes, but I hope that in the next 48 hours we will have some... constructive, positive news," he said after meeting Egyptian President Hosni Mubarak.
Israel has maintained an air and sea embargo since the 14 August ceasefire ended its 34-day conflict with Hezbollah fighters.
Turkish troops would join a UN force tasked with keeping the peace between Israel and Hezbollah guerrillas in south Lebanon.
The government believes involvement in the Lebanon mission would bolster its role within the Middle East and advance its ambition to join the European Union.
The country's foreign minister said on Monday that the number of troops to be deployed would not exceed 1,000.
But the move to send Turkish soldiers faces broad domestic opposition, with many unwilling to engage in a situation in which they could be fighting against fellow Muslims.
In a bid to quell fears, Turkish Prime Minister Recep Tayyip Erdogan assured the public that the soldiers would withdraw if they were asked to disarm Hezbollah.
On Monday, Qatar became the first Arab state to commit troops to the UN peacekeeping force in Lebanon, offering 200 to 300 military personnel.
The UN is installing 15,000 peacekeepers in southern Lebanon as part of UN Security Council Resolution 1701.