Six world powers agreed Thursday on stiff new penalties to level against Iran for its refusal to abandon its nuclear program.

The deal was reached among the five permanent members of the Security Council — the U.S., Russia, China, France, and Britain — as well as Germany.

"We have an agreement, and I will introduce a text on behalf of the six," British Ambassador Emyr Jones Parry said after a meeting of ambassadors from the countries. "It's a text which is our suggestions. It's not 'take it or leave it.'"

The pact is one stage in the process of implementing the proposed measures, which the other 10 members of the UN Security Council will likely approve in a vote next week. The vote date has not yet been set.

The new resolution calls on all UN member states to exercise "vigilance and restraint" on Iranian arms imports. It would also include stricter asset freezes on individuals and companies associated with Tehran's nuclear programs.

The U.S. and the Europeans reportedly favoured even tougher sanctions, but settled for lighter penalties in order to appease Russia and China — countries which both still have close commercial ties with Iran — and ensure they would not use their veto power to block a resolution.

On late Wednesday, acting U.S. ambassador Alejandro Wolff said the six parties had reached "an agreement in principle" after making some additional changes to appease certain delegations.

Wolff, the U.S. envoy, expressed confidence his counterparts from the other five nations would back the sanctions package before it was to be presented to the Security Council on Thursday.

On Wednesday, Iranian President Mahmoud Ahmadinejad warned the West that it would deepen the rift with his country by imposing more UN sanctions.

"You are wrong if you think you can sit and draft … something in order to isolate the Iranian nation," Ahmadinejad said in a speech to several thousand people in the Iranian city of Yazd.

"Not only are you unable to hurt Iran, but you would further isolate yourselves and make yourselves more hated," he added.

The Security Council voted unanimously in December to impose limited sanctions against Iran unless it agreed to suspend uranium enrichment, a process involved in making atomic bombs. The council said it would only tighten the restrictions if Iran continued pursuing its nuclear ambitions. In response, Iran accelerated its enrichment program.

With files from the Associated Press