AMMAN, Jordan — The Islamic State has claimed responsibility for a suicide attack that killed seven members of the Jordanian security forces and wounded 13 others last week at a border crossing with Syria, according to a news agency that transmits reports about the militant group.

The Amaq News Agency published a video on Sunday from the Islamic State, also known as ISIS or ISIL, that purports to show a militant fighter blowing up a vehicle filled with explosives near a military checkpoint in Rukban, Jordan.

The agency cited only an unidentified source, but it has proved to be reliable: It was the first to report that the Islamic State was claiming responsibility for the shootings in San Bernardino, Calif., in December; a deadly rampage in Baghdad in January; and an attack in Indonesia, the same month.

The Jordanian government responded to the attack last Tuesday by sealing its borders with Syria, and aid agencies said that 60,000 refugees living in makeshift camps on the border had received little or no food and water since.

Relief agencies have expressed concern about the effect that the border closing will have on the refugees.

Andrew Harper, the United Nations High Commissioner for Refugees’ representative to Jordan, wrote on Twitter that “unfortunately, no water reached the site again’’ with dust storms and temperatures over 100 degrees Fahrenheit.

Jordan is a crucial United States ally in the region and has been contributing to the air campaign against the Islamic State. Immediately after the attack, which took place at a sand berm marking the frontier, speculation immediately fell on the Islamic State.

“It doesn’t take much imagination to figure out where this is coming from, the murderers who attacked our borders,’’ the country’s foreign minister, Nasser Judeh, told CNN.

The Islamic State did not claim responsibility for two recent attacks in Jordan: An assault this month at an office of the Jordanian intelligence service in a refugee camp near the capital, Amman, that left five people dead, and an attack at an Amman training compound in which five people, including two Americans, were killed.