DAMASCUS - The heightened tension between Moscow and Washington after last week's US missile attack on a Syrian air base appears to be easing, according to analysts.

Relations between Russia and the US were strained by the April 7 strike against the Shayrat air base in central Syria, with Moscow subsequently suspending a flight safety agreement with Washington.

The deal ensured flight safety over Syria,where both Russian and US planes have been carrying airstrikes against the Islamic State group and other radical factions for years.