US Secretary of State John Kerry gives a statement at the airport in Mogadishu, Somalia, Tuesday, May 5, 2015. [Photo/Agencies]

DJIBOUTI - US Secretary of State John Kerry is in Djibouti on Wednesday for talks with the government and to visit a key US military base from where pilots fly missions over Yemen and Somalia.

The United States has beefed up its small consular operations in Djibouti to help process Yemeni-American families fleeing the conflict in Yemen.

As of April 28, the US embassy in Djibouti has assisted more than 500 US citizens arriving from Yemen, the State Department said.

A senior State Department official said Kerry will thank President Ismail Omer Guelleh, who has ruled the country since 1999, for being a dependable ally in the fight against terrorism and for the role it played in evacuations from Yemen.

The United Nations said on Tuesday the conflict in Yemen had taken at least 646 civilian lives since Saudi coalition airstrikes began on March 26, including 131 children and that more than 1,364 civilians had been injured.

Saudi Arabia says the campaign is aimed at restoring President Hadi's government after the Iran-backed Houthis, allied to former president Ali Abdullah Saleh, seized the capital Sanaa in September, put the president under house arrest in January and then advanced south.

The Houthis say their campaign was aimed at fighting al Qaeda militants and to combat corruption.

Kerry heads to Riyadh later on Wednesday to discuss the Saudi bombing campaign against the Houthis, as well as an upcoming summit of Gulf Arab states in Washington.

The Houthi rebels fired rockets and mortars into Saudi Arabia on Tuesday, the first time the Houthis have targeted civilian neighborhoods in the kingdom since the start of the air strikes late March.