MOSCOW, Dec. 18 - President Vladimir Putin assured Russians on Thursday that the economy would rebound after the ruble's dramatic slide this year but offered no remedy for a deepening financial crisis, Reuters reported.

Defiant and confident at a three-hour news conference, Putin blamed the economic problems on external factors and said the crisis over Ukraine was caused by the West, which he accused of building a "virtual" Berlin Wall to contain Russia.

At times sneering, at others cracking jokes, he ignored pressure to say how he will fix an economy facing what his economy minister calls a "perfect storm" of low oil prices, Western sanctions over Ukraine and global financial problems.

The ruble has fallen about 45 percent against the dollar this year, and suffered particularly steep falls on Monday and Tuesday, but Putin refused to call it a crisis and said it would eventually rise again.

"If the situation develops unfavorably, we will have to amend our plans. Beyond doubt, we will have to cut some (spending). But a positive turn and emergence from the current situation are inevitable," Putin said in comments to a packed conference center that were broadcast live to the nation.

Although he said the recovery might take two years, much will depend on how long the West maintains sanctions on Russia over its role in the Ukraine crisis.

European Union diplomats said the 28-nation bloc would ban investment in Crimea from Saturday over Russia's annexation of the Black Sea peninsula and President Barack Obama is set to sign legislation authorizing new U.S. sanctions.

But Putin showed no sign of heeding a call by EU foreign policy chief Federica Mogherini for "a radical change in attitude toward the rest of the world and to switch to a cooperative mode.”

The ruble slipped as he spoke, and was about 2 percent weaker against the dollar on the day. The central bank increased its key lending rate by 6.5 percentage points to 17 percent on Tuesday, and has spent more than $80 billion trying to shore up the ruble this year, but to little avail.

Although Putin said the central bank and government had acted "adequately", he chided the bank for not halting foreign exchange interventions sooner, suggesting more decisive action might have made this week's big rate rise unnecessary.

"All this implies pretty big divisions within the administration as to how to react to the crisis and pressure on the ruble," said Timothy Ash, head of emerging market research at Standard Bank in London, adding that heads could roll.

Neil Shearing, chief emerging markets economist at Capital Economics in London, said Putin signaled no change of policy and capital controls remained "a measure of last resort".

"Whatever happens, a deep recession now looms," he said. (rt/ez)