BAALBEK (Lebanon) - Syrian regime forces backed by fighters of Hezbollah control 80 percent of the strategic town of Qusayr, a source close to the Lebanese Shiite movement said on Sunday.

"We still have to take another 20 percent of Qusayr, since we took 10 percent on Sunday and the rest was already in our hands," the source said, declining to be named.

In addition, "the main road between Baalbek and Homs has been secured," he said, referring to a vital artery through which the powerful Shiite movement sends men and equipment to Syria.

Forces loyal to Syria's President Bashar al-Assad supported by Hezbollah fighters launched an assault on Qusayr a week ago but are still being fiercely resisted by rebels.

Twenty-two Hezbollah fighters were killed in the Qusayr battle on Saturday alone, the source close to the Lebanese group said.

"There were 22 killed on Saturday. Nine bodies were repatriated the same day and the rest on Sunday," the source said.

The Syrian army said Saturday its forces had infiltrated Dabaa military airport, a rebel post north of Qusayr, a week into the offensive to recapture the town near the Lebanese border.

"Fighting is taking place inside the airport after they broke the rebel defence lines," an army source said.

The source close to Hezbollah said the militant group has now lost a total of almost 110 fighters since it joined the battle in Syria several months ago, with most of the deaths in and around Qusayr.

The Syrian Observatory for Human Rights said Hezbollah lost 10 fighters in Qusayr on Saturday, out of a total of 147 people killed in violence across Syria, including 79 rebels, 32 soldiers and 26 civilians.