Afghan insurgents have killed four German soldiers and wounded five others in an ambush in the northern province of Baghlan.

Germany's Defense Ministry says militants attacked the German soldiers' patrol Thursday with rockets. The deaths raise the number of German troops killed in Afghanistan to at least 43 since 2002.

In other violence, Afghan officials say a car bomb exploded near a hotel in the southern city of Kandahar, wounding at least six people. The officials say the blast shattered windows of the hotel and destroyed several nearby vehicles. No other details were immediately available.

Meanwhile, the International Committee of the Red Cross says roadside bombs used by Taliban insurgents have killed an increasing number of Afghan civilians this year.

An ICRC report released Thursday says the number of civilians treated for roadside bomb wounds at a hospital in Kandahar city jumped 40 percent in the first two months of this year, from the same period a year ago.

In another development, the top U.N. official in Afghanistan says a recent series of incidents in which NATO forces killed Afghan civilians represents a "disturbing trend."  In the latest incident, U.S. soldiers fired on a bus near Kandahar City on Monday, killing four civilians.

Staffan de Mistura said Thursday he is deeply saddened and seriously concerned by the deaths, and called on all parties in the conflict to do their "utmost to minimize harm to ordinary Afghans."

Meanwhile, three Italian aid workers accused by Afghan authorities of involvement in a plot to assassinate a southern provincial governor have been transferred to the capital, Kabul. Italy's Foreign Ministry says Italian officials hope to meet with the trio Friday.

Authorities in Afghanistan's Helmand province detained the three representatives of the Italian aid group Emergency earlier this month. The officials said police found weapons in a hospital run by the group and suspected they were to be used in a Taliban plot to kill Helmand's governor.

U.N. envoy de Mistura urged Afghan authorities to carry out a quick and thorough investigation of the case. He said he hopes the arrests of the Italians were due to what he called a serious misunderstanding.


Some information for this report was provided by AP, AFP and Reuters.