LONDON, Oct 3 (Reuters) -

Iran accused Saudi Arabia and Russia on Wednesday of breaking OPEC's agreement on output cuts by producing more crude, adding that the two countries would not be able to produce enough oil to make up for a reduction in Iranian exports.

Reuters reported on Wednesday that Russia and Saudi Arabia struck a private deal in September to raise oil output to cool rising prices and informed the United States before a meeting in Algiers with other producers.

U.S. sanctions on Iran's petroleum sector are set to take effect next month after U.S. President Donald Trump withdrew from the Iran nuclear deal in May.

Washington wants to cut Iran’s oil exports to zero by November, and is encouraging producers such as Saudi Arabia, other OPEC members and Russia to pump more to meet the shortfall.

"If Iran is under sanctions, the price of oil would rise and Russia and Saudi Arabia cannot do anything to supply additional oil to the market," Iran’s OPEC governor Hossein Kazempour Ardebili was quoted as saying by SHANA, the oil ministry’s news agency.

Kazempour Ardebili, Iran's representative on OPEC's board of governors, said that U.S. sanctions on Iranian oil were "impossible", and called on Trump to return to the nuclear deal with Tehran.

"Mr Trump is very angry with some countries for not being able to replace the Iranian oil and has expressed this anger in his remarks to the Saudi king and to OPEC for not increasing output," he said.

“If we look at the two countries’ rise of production in comparison to their commitments in the Declaration of Cooperation, we see Saudi Arabia and Russia have had respectively a 346,000 and 250,000 BPD output rise, and this production rise is a violation to the (OPEC) agreement on output cut,” Kazempour Ardebili said.

Since the meeting in Algiers, Reuters has reported that Riyadh planned to lift output by some 200,000 bpd to 300,000 bpd from September to help fill the gap left by lower Iranian output due to the sanctions.

Russian output rose 150,000 bpd in September.

Trump made an undiplomatic remark about close ally Saudi Arabia on Tuesday, saying he warned Saudi Arabia's King Salman he would not last in power "for two weeks" without the backing of the U.S. military.