Russia on Thursday rejected a European proposal for sanctions on Iran as too tough, amid reports that Tehran is stepping up its nuclear programme.

Sergei Lavrov, foreign minister, said Moscow could not approve a draft United Nations resolution circulated by France, Germany and the UK on Wednesday. The draft would ban or restrict missile sales, the transfer of nuclear technology and travel for people connected to Iran’s nuclear programme.

“Our goal is to eliminate the risks of sensitive technologies getting into the hands of Iran . . . while maintaining all possible channels of communication,” Mr Lavrov said, referring to an understanding thrashed out by the three European Union countries, Russia, China and the US.

“In this context, the draft resolution clearly does not correspond to those tasks agreed on by the six sides,” he added.

Mr Lavrov’s intervention marks the beginning of a struggle between the western countries and Russia and China on the scope and nature of sanctions.

While the EU hopes to agree a resolution by the end of next week, it has to chart a difficult path between John Bolton, US ambassador to the UN, who would like tougher measures, and Moscow and Beijing, which want more limited sanctions. Russia and China have strong economic links to Tehran.

European diplomats also believe there are divisions between Mr Bolton and Condoleezza Rice, secretary of state, and Nicholas Burns, the under-secretary. At issue is the $1bn nuclear reactor Russia is building at Bushehr in Iran.

The current draft exempts construction of Bushehr from sanctions but says other activities – a reference to supplying nuclear fuel at a later stage – must be approved on a case-by-case basis by a sanctions committee. Officials said Russia’s angry response was promp-ted by previous understandings given to Mr Lavrov that Bushehr would not be affected by the resolution.

However, US officials on Thursday denied reports of a split with Europe over the draft and played down serious differences with Russia over the fate of the Bushehr power plant. A State Department spokesman said the US did not think the issue of Bushehr would be an obstacle to getting a “good, strong resolution” that would be binding on Iran.

Iran’s semi-official student news agency, ISNA, has quoted an unnamed Iranian official as saying a second network, or cascade, of 164 centrifuges for uranium enrichment was installed last week, and that injection of the gas feed would take place this week.