MOSCOW, Oct 19 (Reuters) - The Russian rouble strengthened on Wednesday, climbing to a near two-week high against the euro as the finance ministry held just its second OFZ treasury bond auction since Moscow sent tens of thousands of troops into Ukraine in February.

Geopolitical risks and unpredictability continue to buffet Russian markets. President Vladimir Putin introduced martial law on Wednesday in four Ukrainian regions he says are part of Russia.

By 1250 GMT, the rouble was up 1.1% against the euro at 60.10 , earlier reaching 59.4450, its strongest point since Oct. 7.

It was 0.1% weaker against the dollar at 61.62 , earlier coming close to strengthening past the 61 threshold, and had firmed 0.8% against the yuan to 8.44 , a two-week high.

The finance ministry held its first OFZ bond auction in several weeks, enjoying demand of 76.7 billion roubles ($1.24 billion) on a bond placement of 25 billion roubles, with a floating-rate coupon. Promsvyazbank analysts said the ministry last placed a "floater" in November 2020.

Another auction is due later on Wednesday. Strong demand at OFZ auctions supports the rouble.

"The external environment for the rouble-denominated bond market remains contradictory," Promsvyazbank analysts added, pointing to improving global demand for risk assets on the back of U.S. economic data, but with lower oil prices hampering the market.

Brent crude oil , a global benchmark for Russia's main export, was up 1% at $90.9 a barrel, but well away from highs of around $98 a barrel reached early last week.

Russian stock indexes were lower.

The dollar-denominated RTS index (.IRTS) was down 2.7% to 1,011.82 points. The rouble-based MOEX Russian index (.IMOEX) was 2.7% lower at 1,978.3 points.

For Russian equities guide see

For Russian treasury bonds see

($1 = 61.7470 roubles)

Our Standards: The Thomson Reuters Trust Principles.