March 10 (Reuters) - Russian firms have encountered problems in securing financing for April contracts to sell crude and oil products, but the situation can be resolved, Deputy Prime Minister Alexander Novak was quoted as saying by Interfax news agency on Thursday.

The United States banned imports of Moscow's oil and gas on Tuesday, while some Western oil companies, including Shell , have said they will stop buying Russian oil.

Western sanctions have not yet had an impact on Russia's oil production, as the latest data showed its output rising by 55,000 barrels per day (bpd) to 11.1 million bpd in March from February, daily newspaper Kommersant reported, citing data from the Russian energy ministry.

Novak said Russia has been working with the oil companies and the buyers to find other ways of payment, without a need for letters of credit.

"We are finding other ways, for example, with Chinese companies - this is not a comprehensive method, these are isolated cases," he was quoted as saying.

Novak also said that apart from financing, there were also issues with tanker availability as insurers had "taken a pause".

Output from Russia's largest producer, Rosneft, stood at 3.4 million bpd, excluding Bashneft, Lukoil's output was at 1.6 million bpd, Surgutneftegaz's at 1.2 million bpd and Gazprom Neft's at 0.8 million bpd, Kommersant reported the data as showing.

While total production rose, with Gazprom Neft contributing four-fifths of the increase, some Russian producers have faced problems selling their cargoes, Kommersant said.

Surgutneftegaz was repeatedly unable to sell its spot cargoes via the Baltic ports, it added.

Surgutneftegaz declined to comment when contacted by Reuters.

Analysts at Oslo-based Rystad Energy said on Tuesday that Russia might be forced to start shutting down its crude oil production if the embargo widens, as it had to do in April 2020, when global demand crashed due to the COVID-19 pandemic.

"There is nowhere to store the oil onshore, so Russia will be forced in a very immediate timeframe, days, potentially a week or two to shut the oil wells on a very large scale," the analysts said during a webinar. (Reporting by Reuters; Editing by Jason Neely, Mark Potter and Alexander Smith)