A day after meeting with Israeli Prime Minister Benjamin Netanyahu, U.S. National Security Advisor John Bolton met with Israeli President Reuven Rivlin, discussing matters related to Gaza, the Israeli-Palestinian conflict and other Mideast issues.

Rivlin, who welcomed Bolton as “one of the most important guests we’ve hosted here in Israel [to] Jerusalem the capital of Israel, the eternal capital of the Jewish people,” gave his appreciation to the top Trump adviser as “a great friend of the Israeli state and the Israeli people.”

“And we know that you’re going to do more,” added Rivlin.

Nonetheless, the meeting between them was anything but casual.

“We have discussed all the matters that we are very much concerned about—whether we are talking about the Hamas in Gaza or the situation in Syria, the situation with the Hezbollah and the Iranians, of course, and the nuclear ability of Iran,” said the Israeli president.

“It’s a very challenging time for both Israel and the United States,” said Bolton. “I think just underlining the close friendship and alliance between the two governments and peoples of Israel and the United States is always important to do.”

In addition Netanyahu and Rivlin, Bolton met with Israeli Defense Minister Avigdor Lieberman. He also visited Yad Vashem, Israel’s Holocaust memorial museum.

“In memory of the greatest tragedy which the spirit and resilience of the Jewish people has overcome, to help us prevent its like from ever happening again … to anyone,” Bolton wrote in the guestbook, according to a statement from Yad Vashem.