BEIRUT (AP) -- Syria said Sunday it is still negotiating with the Arab League over the bloc's request to send observers into the country, as tightening sanctions by Arab and other nations fail to halt the eight-month crackdown on anti-government protesters.
New violence killed at least six people on Sunday, including a female university professor and a father and his three children in central Syria, opposition activists said.
Arab leaders have given Syria a new deadline of Sunday to respond to the League's peace plan, which calls for the admission of observers to ensure compliance with government cease-fire. They also held out the threat of pushing for U.N. involvement if Syria balks.
Syria's failure to meet a Nov. 25 deadline to allow in observers drew Arab League sanctions, including a ban on dealings with the country's central bank. Together with sanctions from the United States, the European Union and Turkey, the Arab League's penalties are expected to deal significant damage to Syria's economy and may undercut the regime's authority.
The revolt against President Bashar Assad's rule began with peaceful protests in mid-March, triggering a brutal crackdown. The unrest has steadily become bloodier as army defectors join the revolt and some civilians take up arms, prompting the United Nations' human rights chief to refer to it last week as a civil war and urge the international community to protect Syrian civilians.
The U.N. estimates more than 4,000 people have been killed.
Faced with Sunday's new deadline, Syria signaled it still might be willing to comply with the Arab League's plan, saying its objections were simply a matter of details.
"Messages are being exchanged between Syria and the Arab League to reach a certain vision that would facilitate the mission of observers in Syria while preserving Syrian interests and sovereignty," Foreign Ministry spokesman Jihad Makdissi told reporters in Damascus.
Syria, which has already been suspended from the 22-member League, may be playing for time while its crackdown continues. Activists said there was more bloodshed on Sunday as security forces unleashed indiscriminate fire that killed six people in the central province of Homs.
Qatar's prime minister said Saturday during a meeting of Arab foreign ministers in the Gulf country's capital, Doha, that he expected Syrian envoys to sign an agreement on Sunday.
Sheik Hamad Bin Jassem Bin Jabr Al Thani said failure to reach an agreement may lead to U.N. involvement in the Syrian crisis, although he did not spell out what that meant.
Arab ministers have continued to meet to work out enforcement of the existing sanctions package.
Some sanctions -- the central bank ban, a halt to Arab government funding of projects in Syria and a freeze of Syrian government assets -- went into effect immediately.
Saturday's meeting approved a list of 19 Syrian officials subject to a travel ban. Among them are Assad's younger brother Maher, who is believed to be in command of much of the crackdown, as well as Cabinet ministers, intelligence chiefs and security officers. The list does not include the president himself.
International sanctions have left Assad's regime increasingly isolated.
The Syrian government said Sunday it was suspending a 2004 free-trade agreement with Turkey in response to the penalties imposed by its former close ally.
As a reciprocal measure, it added, all Turkish imports would be subject to customs fees.
Turkey, a key NATO member and until recently a close partner of Syria, imposed tough new sanctions against Damascus this week that included the suspension of all ties to the Syrian Central Bank and freezing any Syrian government assets in Turkey. Turkey and Syria did $2.4 billion in trade last year, according to the Turkish Embassy in Damascus.
Associated Press writer Albert Aji contributed to this report from Damascus, Syria.