Defense Minister Moshe Ya'alon has ordered the closure of the Kerem Shalom border crossing between Israel and Gaza, after two rockets fired from the Strip exploded in the southern Israeli town of Sderot early Thursday. The rockets were fired as U.S. President Barack Obama was beginning the second day of his first visit to the country as president. The rockets exploded near the border with the Gaza Strip, causing damage to one house. No casualties were reported.

A second rocket exploded in an open area in Sderot. Two other rocket launches were detected by the IDF, but landed in Gaza.

Ya'alon decided that the crossing will operate for humanitarion purposes only and will be reopened once the security situation permits it.

Political sources in Jerusalem said Israel was not expected to respond to the rocket fire: "The Israeli response will come at the right time and the right place," they said.

Sources also said they were waiting for a clear message of condemnation from Palestinian President Mahmoud Abbas during his own meeting with Obama in Ramallah later Thursday.

"It will be interesting to see if Abbas, who did not condemn the rocket fire during the entirety of Operation Pillar of Defense will do so today," they said. "It is also interesting to see whether this rocket fire, launched from territory controlled by Hamas, will lead the Palestinian Authority chairman to cease his ongoing unification talks with Hamas, a terrorist organization calling for the destruction of Israel."

Shortly after the Jerusalem sources' comments, the official Palestinian Wafa news agency quoted Abbas condemning the rocket fire: "We condemn violence against civilians regardless of its source, including rocket firing."

"We are in favor of maintaining mutual and comprehensive calm in Gaza," Abbas added according to Wafa.

The attack from Gaza, the second such event in less than a month, occurs during Obama's first visit to Israel as president. In the previous incident, a medium-range rocket manufactured in Gaza exploded in Ashkelon's industrial zone.

Earlier this week a senior Hamas official threatened retaliation against Israel for what he called frequent violations of the ceasefire agreement, by Israel. The truce deal was reached following Israel's Pillar of Defense military operation in Gaza in November last year.

The senior official referred to a number of incidents where IDF forces opened fire at Palestinians approaching the Gaza security fence.