The head of Afghanistan's constitutional assembly says delegates are just short of a deal on the nation's future system of government. But disagreement on one issue means agreement on a draft constitution will not be reached before Sunday.

After close to three weeks of heated debate on a new constitution, members are reportedly near agreement.

Debate among members of the constitutional assembly, or "loya jirga," deadlocked Thursday, forcing an adjournment as Afghan and international mediators scrambled to help work out an agreement.

Issues that caused the most heated debate included whether to have a presidential or parliamentary system of government, and which of Afghanistan's many languages should hold official status.

But loya jirga Chairman Sabghatullah Mujadidi said Saturday that delegates have now agreed on all but one issue. While Mr. Mujadidi did not specify which issue was still under debate, he said he hopes the assembly will pass the new constitution Sunday.

Sources close to the assembly say the last unresolved quarrel involves whether to make Uzbek an official language.

Speaking earlier, Afghan transitional President Hamid Karzai told reporters he expected the loya jirga to adopt a constitution in the very near future.

But although the assembly has now run almost two weeks longer than expected, Mr. Karzai added that the constitution should not be rushed through without a general agreement. "It is important to have a constitution that comes with near consensus, if not total consensus," he said.

Following the adoption of the constitution, Afghanistan is expected to hold national elections, currently slated for this summer.