Iran and Hezbollah 'have built 50,000-strong force to help Syrian regime'

Syrian rebels in Idlib province. Israel has warned against arming the fighters in case weapons reach al-Qaida-affiliated groups. Photograph: Hussein Malla/AP

Iran and Hezbollah have built a 50,000-strong parallel force in Syria to help prolong the life of the Assad regime and to maintain their influence after his fall, Israel's military intelligence chief has claimed.

Major General Aviv Kochavi said Iran intended to double the size of this Syrian "people's army", which he claimed was being trained by Hezbollah fighters and funded by Tehran, to bolster a depleted and demoralised Syrian army.

Kochavi, the director of military intelligence in the Israel defence forces (IDF), also said Assad's troops had readied chemical weapons but so far had not been given the order for them to be used.

At the same time, he warned of the increasing sway of extremist groups in the opposition, particularly the al-Nusra Front, which he claimed was beginning to infiltrate Lebanon and was making connections with a Sinai-based militant organisation, Ansar Bait al-Maqdis, which is focused on attacks on Israel.

Israel opposes the western arming of Syrian rebels because of its fears that the weapons will end up in the hands of such groups.