The Arab League chief on Friday asked the Damascus-based leader of the Palestinian group Hamas to ask Syria to work to halt violence, saying there was more to do under a peace agreement aimed at ending a crackdown on anti-government protesters.

Arab League Secretary General Nabil Elaraby was speaking alongside Hamas leader Khaled Meshaal after a meeting in Cairo.

I gave him a message today to the Syrian authorities that it is necessary to work with integrity, transparency and credibility to halt the violence that is happening in Syria, Elaraby said.

The Arab League has sent monitors to Syria to check on the government's compliance with a promise to end 10 months of violence against pro-democracy protesters.

Elaraby said there was still work to be done according to the agreement between the League and Syria to scale back its military presence in cities and free thousands of prisoners detained since the uprising began last March.

The observers are striving to realise this situation: to realise a halt to the violence; to realise the release of the detained, to realise the withdrawal of the (military) vehicles. Therefore there is work, he said.

He also said the Arab monitors were in Syria now to undertake a mission that is bigger than that which was asked of them, but without giving further details.

Elaraby said Meshaal had played a role in convincing the Syrian government to sign the Arab League protocol.

Since the start of the crisis, we in Hamas and myself personally, have made a huge effort to solve the crisis through a political solution, and we have kept up these efforts, Meshaal said.

Damascus is the main Hamas headquarters outside of the Gaza Strip, which it has governed since seizing control there in 2007.

Together with Iran, Syria has been one of Hamas' main regional allies. However, the uprising against President Bashar al-Assad's rule has strained ties between the two.

Angering Syria, Hamas has refused to hold rallies in Palestinian refugee camps in support of the Assad government.

However, the group still officially maintains its headquarters in the Syrian capital.

(Reporting by Ayman Samir; Writing by Tom Perry)