John O. Brennan, President Barak Obama's chief adviser on counter-terrorism, was in Israel on July 25 for talks with the heads of the Israeli intelligence community on the Burgas, Bulgaria terror attack targeting Israelis. Brennan arrived in Israel directly from similar talks in Sofia, the Bulgarian capital.

In Israel, Brennan met with National Security Adviser Brig.-Gen. (ret) Yaakov Amidror, NSC Counter-Terrorism Bureau head Eitan Ben-David and senior officials of the Mossad, the Shin Bet security service and the Israel Defense Forces Intelligence Branch.

A senior U.S. administration official said that Brennan's talks in Israel centered on the progress of the joint investigation around the Burgas attack by U.S., Israeli and Bulgarian intelligence agents. However, the talks touched, in a wider sense, on terror attacks the Iranian Revolutionary Guards and Hezbollah have attempted to mount over the last three years.

A week after the Burgas attacks, Israeli, Bulgarian and U.S. still have no leads on the identity of the suicide bomber. Israel and the U.S. maintain that Hezbollah was behind the attack, but have so far failed to produce substantial evidence to support this assertion. At a joint press conference with Brennan, Bulgarian Prime Minister Boyko Borisov admitted that there was no information concerning the terrorist or those who dispatched him.

According to the senior American official, Brennan's Israeli talks also dealt with the situation in Syria and the level of al-Qaida's involvement in the revolt against the Assad regime, the situation in Sinai and the smuggling of weapons to Palestinian terror organizations in the Gaza Strip.

Long-time CIA veteran Brennan's last post in the Central Intelligence Agency was as head of the National Counterterrorism Center. His affiliation with Obama dates back to the 2008 presidential campaign, and he is considered one of the president's closest adviser. In the White House, he coordinated the U.S. team that carried out the killing of al-Qaida leader Osama bin Laden.

Brennan was the fourth senior American official to visit Israel in 10 days. He was preceded by Deputy Secretary of State Bill Burns, Secretary of State Hillary Clinton and National Security Adviser Tom Donilon. Defense Secretary Leon Panetta is due next Tuesday. The wave of visits of senior Obama administration officials parallels the planned visit by Mitt Romney, the Republican presidential candidate, who is due to land in Israel on Saturday night.