Turkey and Syria traded artillery fire for the fourth day in a row Saturday as rebels clashed with President Bashar Assad's forces near the border, heightening fears that the crisis could erupt into a regional conflict.
Also Saturday, Syrian Defense Minister Gen. Fahd Jassem al-Freij vowed to crush the rebellion and bring the violence that has engulfed the country to an end.
The diplomatic crisis began on Wednesday, when a Syrian shell killed five civilians in a Turkish border town and triggered unprecedented artillery strikes by Turkey. Ankara has deployed more troops to its southern border with Syria, and has responded to each shell that has struck Turkish soil with its own artillery barrage.
Saturday's cross-border exchange began when two mortar shells fired from Syria landed in rural areas near the Turkish village of Guvecci, prompting Turkish return fire, Turkey's media reported.
Later Saturday, a third shell hit near another village in Turkey's Hatay province and Turkish troops fired back, the office of the provincial governor said.
No casualties were reported.
The first exchange happened shortly after intense fighting broke out across the border in Syria's Idlib province between Syrian rebels and regime forces, the private Dogan news agency reported.
A Turkish army unit based near Guvecci fired four 81 mm mortar shells in the first instance and two shells in the second, it said. No casualties were reported.
The Hatay governor's office indicated that the Syrian mortar had landed in Turkey accidentally, saying it was believed "to be have been fired by the forces of the Syrian Arab Republic at Syrian rebel groups on the Syrian side of the border."
The Britain-based Syrian Observatory for Human Rights said rebels had attacked army positions in the Syrian villages of Khirbet al-Jouz and Darkoush about 16 kilometers (10 miles) from Guvecci. Observatory director Rami Abdul-Rahman said both sides were exchanging mortar fire.
The Observatory added that rebels later took over Khirbet el-Jouz and were advancing toward army positions in nearby areas. It said dozens of soldiers were either killed or wounded while three rebels died in the fighting.
Relations between Turkey and Syria, once strong allies, deteriorated sharply after the uprising against Assad began in March last year. Turkey became one of the harshest critics of Assad's crackdown while Syria accused Ankara of aiding rebels.
Turkish Foreign Minister Ahmet Davutoglu told Turkey's state television TRT that "from now on whenever there is an attack on Turkey, it will be silenced."
Also Saturday, Assad made a rare public appearance when he laid a wreath at the country's Unknown Soldier statue in Damascus to mark the anniversary of the 1973 war with Israel, also known in Syria as the October War. Syrian state television broadcast the ceremony and likened the current crisis to the war with Israel.
Syria's defense minister said Saturday that the government is ready to give amnesty to rebels who repent and those who don't "will be crushed under the feet of our soldiers."
Al-Freij, who became defense minister in July after his predecessor was assassinated, also claimed that the regime was getting the upper hand. "The most dangerous parts of the conspiracy have been passed and the killing is on its way to decline," he said.
The defense minister, who rarely makes public comments, spoke as Syrian troops launched a major offensive to retake rebel-held areas in the northern city of Aleppo, the central city of Homs and towns near the border with Lebanon.
Despite his claims of government troops being on the brink of restoring stability, the violence across the country shows no signs of abating. Activists say that at least 30,000 people have been killed since the anti-Assad uprising began.
Lebanese security officials said Syrian troops backed by warplanes and helicopter gunships began a major attack against rebel-held areas near the Syrian town of Quseir adjoining Lebanon's Bekaa Valley. The Lebanese-Syrian border has also been the site of deadly border incidents.
The officials, who spoke on condition of anonymity in line with regulations, said Lebanese troops were put on high alert along the border.
The Observatory and the Local Coordination Committees, another activist group, reported intense shelling in rebel-held areas of Aleppo and Homs. They said the government shelling of the town of Taibeh near Homs killed at least 10 people and wounded dozens.
A Syrian official said government troops captured the strategic Sakhour roundabout in Aleppo on Saturday after days of heavy fighting. The official spoke on condition of anonymity because he was not authorized to speak to the media.
The fight for Aleppo, a city of 3 million that was once a bastion of support for Assad, is critical for both the regime and the opposition. Its fall would give the opposition a major strategic victory and control of a stronghold in the north near the Turkish border. A rebel defeat, at the very least, would buy Assad more time.
Also Saturday, Iran asked international organizations to help free 48 Iranians purportedly being held by rebels since Aug. 4. Foreign Ministry spokesman Ramin Mehmanparast said Iran holds the armed Syrian opposition groups responsible for the lives of the captives, the IRNA news agency reported.
Iran says those abducted were pilgrims visiting a Shiite shrine in Damascus, but Syrian opposition groups claim they are members of the elite Revolutionary Guard assisting the regime.
In an amateur video posted late Thursday, a rebel group claiming to hold the Iranians said it would begin killing them within 48 hours unless the regime met a series of demands, including halting military operations against the opposition.