A top aide to U.S. President Barack Obama on Wednesday met with Israeli officials over a range of "shared security concerns," the White House said.

The recent wave of "terrorist plots" against Israeli and other interests also topped the agenda of John Brennan, assistant to Obama for homeland security and counterterrorism, the White House said in a statement.

Five Israelis were killed last Wednesday when a powerful blast ripped through a bus with Israeli tourists onboard at Burgas airport in Bulgaria. Israeli officials have blamed Iran and the Hezbollah militant group for the attack.

During his one-day trip to Israel, Brennan also had a " productive" meeting with Palestinian Prime Minister Salam Fayyad in Jerusalem, the White House said.

Obama, who has not set foot on Israel during his presidency, has sent Thomas Donilon, his national security advisor, and Secretary of State Hillary Clinton to the country this month amid concerns over the worsening violence in Syria and Iran's intransigency over its disputed nuclear program.

The campaign of Mitt Romney, the presumptive Republican presidential nominee who is going to face Obama in the November elections, has attacked the president over his foreign policy records, including Israel's exclusion from his foreign trips.

Romney left on Tuesday for a visit to Britain, Poland and Israel, a journey regarded as his attempt to furbish his foreign policy credentials.