Qatar will need help from the United States to persuade Doha’s natural gas buyers to reroute some supplies to Europe in case a Russia-Ukraine conflict disrupts Russian deliveries to the continent, a source familiar with the discussions said. The issue will be discussed at talks in Washington next week between the Emir of Qatar Sheikh Tamim bin Hamad al-Thani and US President Joe Biden, one of the sources said. The US administration has in recent weeks approached Doha and other major energy producers to see if they can help in case Russia attacks Ukraine and the United States imposes sanctions …