Group A pits Italy, Turkey, Wales and Switzerland with matches to be played in Rome and Baku.
The trio joins other big names such as world champions France, Spain, Italy, and England, with European champions Portugal one win away from qualification.
European champions Portugal and high-flying Ukraine edged closer to reaching next year’s European Championship with comfortable home wins in qualifying Group B on Friday.
Players from all 55 of UEFA's national associations will look to qualify for the final tournament in London from July 9-10, a couple of days before the final of the real-world European Championship at Wembley Stadium on July 12.
Southgate, who plans to consult his players before the Oct. 14 game, said he feared they could face racial abuse in Bulgaria after an away fan allegedly targeted winger Raheem Sterling when the teams met at Wembley last Saturday.
Captain Ronaldo, making his 160th international appearance, scored four as Portugal won 5-1 in Vilnius and strengthened their position in Group B after a sluggish start.
All three goals scored in the first half of the match precipitated Turkey's first loss in the qualification matches after three wins in a row.
Turkey has issued a diplomatic note to Iceland condemning the ill-treatment of the footballers. The national football team were not allowed to leave Keflavik Airport for over three hours and their luggage was painstakingly searched, players said.
Cenk Tosun scored twice, continuing Turkey's strong start to the Euro 2020 qualifying campaign.
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