NEW DELHI, March 18 Reuters Oil prices ticked up in Asian trade on Monday, extending gains from last week of nearly 4 on the view that supply was tightening, with the risks heightened by further attacks on Russian energy infrastructure.

Brent crude oil futures for May delivery climbed 47 cents, or 0.5, to 85.81 a barrel by 0720 GMT. The April contract for U.S. West Texas Intermediate WTI crude was up 49 cents, or 0.6, at 81.53. The more active May delivery contract for WTI traded 50 cents, or 0.6, higher at 81.08 per barrel.

The strikes on Russian refineries added 23 per barrel of risk premium to crude last week, which remains in place as we start this week with more attacks over the weekend, said Vandana Hari, founder of oil market analysis provider Vanda Insights.

But for the next substantial move up or down, crude will await fresh signals, Hari added.

On Saturday, one of the strikes sparked a brief fire at the Slavyansk refinery in Kasnodar, which processes 8.5 million metric tons of crude oil a year, or 170,000 barrels per day.

A Reuters analysis found the attacks have idled around 7 of Russian refining capacity in the first quarter. The refining complexes process and export crude varieties to several markets including China and India.

In the Middle East, Israeli Prime Minister Benjamin Netanyahu confirmed on Sunday he will proceed with plans to push into Gaza39;s Rafah enclave where more than 1 million displaced people are sheltering, defying pressure from…