US Treasury yields were higher on Monday ahead of an expected interest rate cut at this week's Federal Reserve policy meeting and as the latest Brexit developments boosted the British pound and market appetite for risk. The European Union agreed to a three-month flexible Brexit delay on Monday but the British parliament rejected Prime Minister Boris Johnson's bid to end the political paralysis with a Dec. 12 election. Allowing Britain more time to come to a consensus lowers chances of a no-deal exit, reducing uncertainty and with it, investor demand for safe-haven investments like US government bonds.

That outweighed the potential uncertainty brought about by Johnson's third failure to call a snap election. Though yields ticked down following the election news, they remained higher on the day. The benchmark 10-year yield was last up 4.4 basis points at 1.846%, with the 30-year yield up 4.5 basis points at 2.338%. With "the risk-positive impulse from the Brexit extension, (it) makes sense that rates are coming back higher. From a technical lens, we broke a couple pretty significant support points, which suggests that 10s could sell off further from here. In particular, we're watching that 1.90% level," said Jon Hill, US rate strategist at BMO Capital Markets.

At the conclusion of its two-day policy meeting on Wednesday, the Federal Open Market Committee is widely expected to cut interest rates by 25 basis points for the third time this year. Traders' expectations of an October cut were 95.1% on Monday, compared with 89.8% a week prior, according to CME Group's FedWatch tool. The two-year Treasury yield, which reflects investor expectations of changes in interest-rate policy, was up 1.9 basis points to 1.646%.

But some analysts are expecting a hawkish statement to accompany the cut, which would suggest a pause in Fed rate cuts after October. "The base case is something like a hawkish cut, by which they cut one more time, that sets a 75-basis-point parallel to the late 90s. And then they try to set up being on pause from here," said Hill. "I don't expect them to seriously commit to not cutting again. Instead they'll try to keep flexibility. But at least moderate expectations for a fourth cut in December."