Several Syrian missiles landed in neighboring Jordan Sunday, witnesses and security sources said, as Damascus renewed its aerial bombardment of rebel-held areas along the border and elsewhere.

Residents said several missiles landed in the northern village of Thneibat, setting several hectares of farmland ablaze. Jordanian security sources confirmed the missile landings, saying no casualties or damage was reported.

The incident came less than 24 hours after Syrian missiles reportedly landed near the village of Sama Sahran outside the city of Mafraq. The area hosts most of the 500,000 Syrians who have sought refuge in Jordan during the two-year conflict.

Meanwhile, a rebel source told DPA that two air force generals defected to Jordan on Sunday. The two reportedly flew their MiG-21 fighter jets across the border to Ramtha.

Jordanian security officials denied that any Syrian aircraft had landed Sunday.

Amman has granted asylum to some 50 Syrian air force pilots and around 6,000 military officers so far.

Violence intensified on the Syrian side of the 370-kilometer border Sunday, the Local Coordination Committees said.

The opposition group said heavy shelling was reported in the villages of al-Taybeh, Shajareh, Um al-Mayathan and al-Naiman.

Residents said Free Syrian Army has been withdrawing its forces in face of the air offensive, which began two weeks ago.

"As of this week, there are no Free Syrian Army forces on the ground - we are all alone," said Mohammed al-Saud, a 35-year-old resident of Dalaa. The village was taken by rebel forces last month and has been targeted in the offensive.

Rebel sources however refuted the claim, saying they were regrouping in advance of a counter-offensive.

The Syrian Observatory for Human Rights, a watchdog based in Britain, reported heavy shelling and ground fighting in Douma, a suburb north-east of the capital Damascus, and further north in the provinces of Idlib and Aleppo.

The organization said government troops and rebel forces were battling for control of the Abu al-Dhuheir military airport outside Idlib.

At least 70,000 people have been killed in Syria since the uprising against the regime of President Bashar al-Assad began in March 2011, according to UN estimates. The LCC said at least 45 people were killed across Syria on Sunday alone.