HizbullahIsrael news photo: Flash 90

Three members of the Hizbullah terrorist organization and 12 Syrian rebels were killed in fierce battles near Syria’s border with Lebanon on Sunday, security sources said, according to the Daily Star daily newspaper.

The fighting, the worst near the border with Lebanon since the uprising erupted in Syria nearly two years ago, underlined Hizbullah’s increasing involvement in the Syrian crisis, the report said.

It also renewed fears of the Syrian conflict between government troops and opposition groups fighting to topple the regime of Syrian President Bashar Assad spilling over into Lebanon.

“In the past two days, 12 Syrian rebels were killed and 30 wounded, while three Hizbullah members were killed and 14 others were wounded in battles,” a Lebanese security source told The Daily Star.

Speaking on condition of anonymity because of the sensitivity of the situation, the source said the fighting between Hizbullah and rebels in the Syrian region of Qusayr, where many Lebanese Shiites reside, has intensified since Friday.

Qusayr is located just across the northeastern border with Lebanon.

During the battles that raged with Syrian rebels over the weekend in Qusayr, Hizbullah guerillas managed to impose their control on some territory and houses vacated by residents of Shiite villages, the source said. The homes had been vacated during confrontations between the two sides several months ago, the source added.

Two artillery shells fired by Syrian rebels landed inside the Lebanese town of Qasr on the border with Syria, causing no casualties, the source told The Daily Star. The first shell did not explode, while the other one hit the wall of a home.

A source close to Hizbullah confirmed the clashes with Syrian rebels in Shiite villages. He said that Hizbullah chief Hassan Nasrallah had previously referred to these clashes when he said that Lebanese Shiite residents were defending themselves against attacks by Syrian rebels.

Blaming the Syrian opposition for the outbreak of fighting, the source said that the villages which Hizbullah members are defending are not located in the center of Syria, but are near the border and their residents are Lebanese.

The report verifies the ongoing claims that Hizbullah is taking an active part in the fighting with Syria and supporting Assad’s troops.

Last July, as the ongoing civil war in Syria continued, Nasrallah's terror group publicly offered to place itself at Assad’s disposal.

Several months earlier, a soldier from the Free Syrian Army told The Independent newspaper, published in the UK, that Hizbullah's Shiite Muslim terrorists are full military allies of the Syrian army and that "everyone knows they have fighters there."

U.S. and Middle Eastern officials said last week that both Iran and Hizbullah are building a network of militias inside Syria to preserve and protect their interests in the event that Assad’s government falls or is forced to retreat from Damascus.

According to the sources, the militias are fighting alongside Syrian government forces to keep Assad in power. Officials believe, however, that Iran’s long-term goal is to have reliable operatives in place in the event that Syria fractures into separate ethnic and sectarian enclaves.

A Lebanese MP charged on the weekend that Lebanon is supplying Assad’s armed forces with explosives.

Lebanon’s Future bloc MP Khaled Daher revealed at a news conference Saturday that trucks have been carrying tons of explosives across the country’s eastern border to Syria for months.