Oil prices strengthened on Friday as global supplies remained tight and the market awaited news from Washington on possible new U.S. sanctions against Iran.

U.S. West Texas Intermediate (WTI) crude ended Friday's session up $1.29, or 1.9 percent, at $69.72 per barrel, the contract's best settle since Nov. 26, 2014. The contract rose to an intraday high of $69.97, its best level since Nov. 28, 2014.

Brent crude oil futures were at $74.90 per barrel, up $1.28, or 1.7 percent by 2:29 p.m. ET. The benchmark contract hit a 3-½ year closing high of $75.17 on Monday.

ANZ analysts Daniel Hynes and Soni Kumari said Brent could reach $80 a barrel by the end of this year, attributing recent strength to rising geopolitical risks and tighter global supply.

"We expect the market to tighten even further in second half 2018," they wrote in a note to clients.