LONDON (TheDeal) -- European stock indices were mixed on Tuesday, with mainland gauges ceding some of yesterday's strong gains as the Federal Reserve prepared to begin a two-day policy meeting and the Bank of Japan opted to retain monetary stimuli.

In London, the FTSE 100 was up 0.35% at 6,827.77. In Frankfurt, the DAX declined 0.96% to 12,051.35. In Paris, the CAC 40 slid 0.23% to 5,049.60.

In Germany a ZEW index of analysts' and investors' economic sentiment came in well under expectations at 54.8 in March, compared with a 53.0 reading in February.

In the eurozone, updated figures from the European Union's statistics arm showed consumer prices fell 0.3% from a year earlier in February, matching a preliminary report.

In London, Tullow Oil (TUWLF) led the FTSE 100 gainers, rising well over 5% after delivering an update on Kenyan exploration.

Mining stocks also gained, including BHP Billiton (BHP) - Get Report, which made the case for the spinoff of its alumina, aluminum, coal, nickel, manganese, silver, lead and zinc assets and said the entity would start life with less debt than expected. Shareholders vote on the demerger on May 6.

J Sainsbury (JSAIY) moved higher after posting a 1.9% quarterly decline in same-store sales and a 0.3% total decline. It blamed the figures on price cuts and food-price deflation and said overall volume had increased.

In Frankfurt, luxury goods maker Hugo Boss (BOSSY) ceded early gains to trade little changed by late morning after private equity firm Permirasold its remaining 12% stake. The sale will increase Hugo Boss free float to 91% from 50% just 10 months ago.

Shares in Volkswagen (VLKAY) rose after figures on European car registration in February suggested it was one of the beneficiaries of a 7% increase.

In Istanbul, wireless service provider Turkcell Iletisim Hizmetleri (TKC) - Get Report was up about 2% after Russia's Alfa Telecom offered $2.8 billion to buy back almost 14% of Turkcell to regain the initiative from one of Turkcell's founders, with whom it has been vying for control.

In Tokyo, the Nikkei 225 ended up 0.99% at 19,437.00, a new 15-year high, and the Topix gained 0.79% to close at 1,570.50.

Tokyo Gas (TKGSF) closed up 2.3% on reports of a ¥50 billion ($440 million) share buyback.

In Hong Kong, the Hang Seng declined 0.20% to 23,901.49, while mainland indices posted strong gains after Chinese Premier Li Keqiang over the weekend pledged support for the economy if growth slows.