Oil prices slipped on Friday as some investors opted to cash out after Brent touched 16-month a high on Thursday, with optimism over this week's OPEC-Russia accord on cutting output giving way to questions on the "sticking point" of implementing the deal.

U.S. crude oil CLc1 added to overnight gains of 9 percent to reach $50.00 a barrel for the first time since October. Brent crude LCOc1, which soared $4 overnight, touched a six-week peak of $52.73 a barrel.

Brent crude, the international oil marker, rose more than $3.00, or 7.2 per cent, to $49.73 in the late morning in London.

The expected fiscal consolidation and the subdued nature of the recovery are putting in place the conditions for the central bank to resume, in due course, monetary policy easing in a manner consistent with the 4 percent inflation target. However, the pace of easing should take into account the presence of external risks and the need to build credibility under the newly introduced inflation targeting regime.

Brent crude futures LCOc1 fell as far as 2 percent before clawing back to trade up 29 cents at $47.44 per barrel at 1008 GMT. U.S. West Texas Intermediate (WTI) crude futures CLc1 also recouped early losses and were trading up 15 cents at $46.21 per barrel.

“We expect demand to recover in 2017, then prices will stabilize, and this will happen without an intervention from OPEC,” Al-Falih said in Dhahran, eastern Saudi Arabia, on Sunday, according to the Saudi newspaper Asharq al-Awsat. “We don’t have a single path which is to cut production at the OPEC meeting, we can also depend on recovery in consumption, especially from the U.S.”

"The general trend and public statements suggest that OPEC can reach a viable agreement for its production and market management." "If we can agree, and I am optimistic, (oil) prices will increase and this is also what the world economy demands."

"Libya is in such a dangerous economic situation, there is no way it can participate in OPEC production cuts for the foreseeable future," NOC Chairman Mustafa Sanalla told delegates at the Arab-Austrian Economic Forum in Vienna on Friday, according to an NOC statement.

“Security and access to funding are the biggest challenges right now to private sector players,” says Kola Karim, managing director of domestic producer Shoreline Energy. “The situation is really tough.”

At 1040 GMT (5:40 a.m. ET), Brent crude futures LCOc1 were trading at $48.89, down 6 cents from their close. U.S. West Texas Intermediate (WTI) crude CLc1 was down 2 cents at $47.94 per barrel.

Iran and Iraq emerged as major stumbling blocks to an OPEC agreement on reducing crude-oil output, as cartel members gathered ahead of their official meeting to tackle the thorny puzzle of how to share the pain of reducing their production

Brent crude oil futures LCOc1 were up 85 cents a barrel at $49.75 by 1000 GMT (5:00 a.m. ET), having earlier risen $1 in a push against the $50 mark for the first time since the end of October. U.S. West Texas Intermediate (WTI) crude futures CLc1 were up 68 cents, or 1.4 percent, at $48.92 a barrel.

Nigeria, which was Africa's largest oil producer until a few months ago, slipped into recession after its economy shrank by 2.06% in Q2, as the impact of militant attacks on oil facilities weighed on the country's economy.

Brent crude oil LCOc1 was up 60 cents a barrel at $47.23 by 1120 GMT (6:20 a.m. ET). U.S. light crude CLc1 was up 50 cents at $46.07.

"We will do everything that our partners from OPEC are expecting. To freeze oil production is not an issue for us," Putin told a news conference in Lima after the APEC summit.