Provocative, issue-oriented advertising isn’t new in Washington’s transit system. Interest groups often plaster Metro’s buses, trains and stations with head-turning messages, occasionally using language and images that some find offensive.

Now comes a photo of Adolf Hitler.

The pro-Israel group American Freedom Defense Initiative (AFDI), angered by anti-Israel ads that recently appeared on some Metrobuses, has countered with a big ad of its own, featuring the Nazi dictator.

Here is AFDI’s message, about 15 feet long, which debuted Monday on the sides of 20 buses and will continue appearing until the middle of next month. …

“Our ads are in response to the vicious Jew-hating ads … unleashed on Washington DC Metro buses last month,” AFDI says on its Web site. AFDI, based in New York, has been labeled an anti-Muslim hate group by the Southern Poverty Law Center, a civil-rights organization that monitors extremist groups.

The “Jew-hating” ad in question, paid for by the Illinois-based group American Muslims for Palestine, appeared on 20 Metro buses from mid-March to mid-April. Here it is. …

The AFDI ad shows Hitler meeting with Haj Amin al-Husseini, the Palestinian nationalist and grand mufti of Jerusalem who allied himself with the Third Reich before and during World War II. Besides making propaganda broadcasts for the Nazis and recruiting European Muslims to serve in the Waffen SS, Husseini backed Hitler’s policy of exterminating Jews.

AFDI’s president, Pamela Geller, did not respond to an e-mail seeking comment on the ad.

At American Muslims for Palestine, spokeswoman Kristin Szremski said: “We typically don’t react to Pamela Geller, because this is the kind of thing she does, countering political speech with racist, Islamophobic speech.” Metro spokesman Dan Stessel declined to discuss the ad, beyond confirming that it will appear on 20 buses for a month. “Media attention is what the advertiser is seeking, and we’re not going to help her,” Stessel said in an e-mail.

Metro, which readily accepted the AFDI ad, tangled with the group in court over advertising in 2012 — and lost.

In September that year, AFDI bought ad space in four subway stations for this message: “In Any War Between the Civilized Man and the Savage, Support the Civilized Man. Support Israel. Defeat Jihad.”

Metro wanted to delay displaying the ads because of an outbreak of violence in the Middle East at the time, sparked by an Internet video that disparaged the prophet Muhammad. After AFDI sued the transit agency on First Amendment grounds, a federal judge in Washington ordered the ads to be posted.