The leader of Lebanon's Hezbollah movement has said he will send more fighters to Syria's Aleppo area, a battleground where it has suffered heavy losses fighting alongside Syrian government forces against rebel groups.

Hassan Nasrallah said on Friday that thousands of Hezbollah's Sunni foes had recently entered Syria via the Turkish border with the aim of taking over Aleppo and its surrounding countryside.

"We are facing a new wave...of projects of war against Syria which are being waged in northern Syria, particularly in the Aleppo region," Nasrallah said in a speech broadcast live on the group's Al Manar TV.

Shia, Iranian-backed Hezbollah has long supported President Bashar al-Assad against mostly Sunni rebels.

"The defence of Aleppo is the defence of the rest of Syria, it is the defence of Damascus, it is also the defence of Lebanon, and of Iraq," he said.

"We will increase our presence in Aleppo," he said. "Retreat is not permissible."

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Nasrallah also denied Hezbollah was in imminent fiscal trouble as a result of a US law banning banks worldwide from dealing with the group.

Last month, Lebanon's central bank instructed the country's banks and financial institutions to comply with the new measure.

But Nasrallah said on Friday that Hezbollah would not be affected because it receives its money directly from Iran, not via Lebanese banks.

"We do not have any business projects or investments via banks," Nasrallah said, insisting the group "will not be affected".

"We are open about the fact that Hezbollah's budget, its income, its expenses, everything it eats and drinks, its weapons and rockets, are from the Islamic Republic of Iran," he added.

Iran was instrumental in Hezbollah's inception three decades ago and has provided financial and military support to the group.

The divided city

Aleppo has been a focus of intensified fighting in the months since peace talks in Geneva broke down and a ceasefire deal brokered by Washington and Moscow unravelled.

Russia intervened in the five-year-old conflict in September with an air campaign to support Assad.

The city is split between government and rebel control. Russian and Syrian warplanes have pounded a road leading from the rebel-held areas north towards the Turkish border.

That major rebel supply line from Turkey to Aleppo city was effectively cut by government advances earlier this year.

Nasrallah said that 26 Hezbollah fighters had been killed in June alone, a rare acknowledgment of the toll their involvement was taking.

Several of its senior military commanders have died in the Syrian conflict, alongside hundreds of fighters.

Source: Agencies